Clang: Improve project part updating

The project part ids are now already created very early in the database.
This removes some checks because we can assume that an id already exists.
The project part are now completely persistent, so we can read them from
the database and compare them with new generated from a new creator
session. This should help to not recreate the same PCH again and again.

Task-number: QTCREATORBUG-21151
Change-Id: Iced818ff9f7431eaed3e37978087cc0a43b9afda
Reviewed-by: Ivan Donchevskii <ivan.donchevskii@qt.io>

66 files changed, 1079 insertions, 639 deletions

diff --git a/src/libs/clangsupport/clangpathwatcher.h b/src/libs/clangsupport/clangpathwatcher.h
index 258c63e938..dab52996c2 100644
--- a/src/libs/clangsupport/clangpathwatcher.h
+++ b/src/libs/clangsupport/clangpathwatcher.h
@@ -38,7 +38,7 @@ namespace ClangBackEnd {
 class WatcherEntry
 {
 public:
-    int id;
+    ProjectPartId id;
     FilePathId pathId;
 
     friend bool operator==(WatcherEntry first, WatcherEntry second)
@@ -69,13 +69,6 @@ public:
 
 using WatcherEntries = std::vector<WatcherEntry>;
 
-using IdCache = StringCache<Utils::SmallString,
-                            Utils::SmallStringView,
-                            int,
-                            NonLockingMutex,
-                            decltype(&Utils::compare),
-                            Utils::compare>;
-
 template <typename FileSystemWatcher,
           typename Timer>
 class CLANGSUPPORT_GCCEXPORT ClangPathWatcher : public ClangPathWatcherInterface
@@ -109,9 +102,9 @@ public:
         removeUnusedEntries(entriesAndIds.first, entriesAndIds.second);
     }
 
-    void removeIds(const Utils::SmallStringVector &ids) override
+    void removeIds(const ProjectPartIds &ids) override
     {
-        auto removedEntries = removeIdsFromWatchedEntries(convertToIdNumbers(ids));
+        auto removedEntries = removeIdsFromWatchedEntries(ids);
 
         auto filteredPaths = filterNotWatchedPaths(removedEntries);
 
@@ -124,7 +117,6 @@ public:
         m_notifier = notifier;
     }
 
-unittest_public:
     static std::vector<uint> idsFromIdPaths(const std::vector<IdPaths> &idPaths)
     {
         std::vector<uint> ids;
@@ -144,15 +136,6 @@ unittest_public:
         return ids;
     }
 
-    std::vector<int> convertToIdNumbers(const Utils::SmallStringVector &ids)
-    {
-        std::vector<int> idNumbers = m_idCache.stringIds(ids);
-
-        std::sort(idNumbers.begin(), idNumbers.end());
-
-        return idNumbers;
-    }
-
     std::size_t sizeOfIdPaths(const std::vector<IdPaths> &idPaths)
     {
         auto sumSize = [] (std::size_t size, const IdPaths &idPath) {
@@ -162,20 +145,19 @@ unittest_public:
         return std::accumulate(idPaths.begin(), idPaths.end(), std::size_t(0), sumSize);
     }
 
-
-    std::pair<WatcherEntries, std::vector<int>>
-    convertIdPathsToWatcherEntriesAndIds(const std::vector<IdPaths> &idPaths)
+    std::pair<WatcherEntries, ProjectPartIds> convertIdPathsToWatcherEntriesAndIds(
+        const std::vector<IdPaths> &idPaths)
     {
         WatcherEntries entries;
         entries.reserve(sizeOfIdPaths(idPaths));
-        std::vector<int> ids;
+        ProjectPartIds ids;
         ids.reserve(ids.size());
 
         auto outputIterator = std::back_inserter(entries);
 
         for (const IdPaths &idPath : idPaths)
         {
-            int id = m_idCache.stringId(idPath.id);
+            ProjectPartId id = idPath.id;
 
             ids.push_back(id);
 
@@ -203,8 +185,7 @@ unittest_public:
             m_fileSystemWatcher.addPaths(convertWatcherEntriesToQStringList(filteredPaths));
     }
 
-    void removeUnusedEntries(const WatcherEntries &entries,
-                             const std::vector<int> &ids)
+    void removeUnusedEntries(const WatcherEntries &entries, const ProjectPartIds &ids)
     {
         auto oldEntries = notAnymoreWatchedEntriesWithIds(entries, ids);
 
@@ -286,9 +267,8 @@ unittest_public:
         return notAnymoreWatchedEntries;
     }
 
-    WatcherEntries notAnymoreWatchedEntriesWithIds(
-            const WatcherEntries &newEntries,
-            const std::vector<int> &ids) const
+    WatcherEntries notAnymoreWatchedEntriesWithIds(const WatcherEntries &newEntries,
+                                                   const ProjectPartIds &ids) const
     {
         auto oldEntries = notAnymoreWatchedEntries(newEntries, std::less<WatcherEntry>());
 
@@ -345,16 +325,13 @@ unittest_public:
         return m_watchedEntries;
     }
 
-    WatcherEntries removeIdsFromWatchedEntries(const std::vector<int> &ids)
+    WatcherEntries removeIdsFromWatchedEntries(const ProjectPartIds &ids)
     {
-
-        auto keep = [&] (WatcherEntry entry) {
+        auto keep = [&](WatcherEntry entry) {
             return !std::binary_search(ids.begin(), ids.end(), entry.id);
         };
 
-        auto found = std::stable_partition(m_watchedEntries.begin(),
-                                           m_watchedEntries.end(),
-                                           keep);
+        auto found = std::stable_partition(m_watchedEntries.begin(), m_watchedEntries.end(), keep);
 
         WatcherEntries removedEntries(found, m_watchedEntries.end());
 
@@ -410,22 +387,20 @@ unittest_public:
         return watchedFilePathIds;
     }
 
-    Utils::SmallStringVector idsForWatcherEntries(const WatcherEntries &foundEntries)
+    ProjectPartIds idsForWatcherEntries(const WatcherEntries &foundEntries)
     {
-        Utils::SmallStringVector ids;
+        ProjectPartIds ids;
         ids.reserve(foundEntries.size());
 
         std::transform(foundEntries.begin(),
                        foundEntries.end(),
                        std::back_inserter(ids),
-                       [&] (WatcherEntry entry) {
-            return Utils::SmallString(m_idCache.string(entry.id));
-        });
+                       [&](WatcherEntry entry) { return entry.id; });
 
         return ids;
     }
 
-    Utils::SmallStringVector uniqueIds(Utils::SmallStringVector &&ids)
+    ProjectPartIds uniqueIds(ProjectPartIds &&ids)
     {
         std::sort(ids.begin(), ids.end());
         auto newEnd = std::unique(ids.begin(), ids.end());
@@ -439,7 +414,7 @@ unittest_public:
         if (m_notifier) {
             WatcherEntries foundEntries = watchedEntriesForPaths(std::move(filePathIds));
 
-            Utils::SmallStringVector changedIds = idsForWatcherEntries(foundEntries);
+            ProjectPartIds changedIds = idsForWatcherEntries(foundEntries);
 
             m_notifier->pathsWithIdsChanged(uniqueIds(std::move(changedIds)));
             m_notifier->pathsChanged(watchedPaths(filePathIds));
@@ -451,13 +426,7 @@ unittest_public:
         return m_pathCache;
     }
 
-    IdCache &idCache()
-    {
-        return m_idCache;
-    }
-
 private:
-    IdCache m_idCache;
     WatcherEntries m_watchedEntries;
     ChangedFilePathCompressor<Timer> m_changedFilePathCompressor;
     FileSystemWatcher m_fileSystemWatcher;
diff --git a/src/libs/clangsupport/clangpathwatcherinterface.h b/src/libs/clangsupport/clangpathwatcherinterface.h
index 2a290561cd..1b478fd19a 100644
--- a/src/libs/clangsupport/clangpathwatcherinterface.h
+++ b/src/libs/clangsupport/clangpathwatcherinterface.h
@@ -41,7 +41,7 @@ public:
     ClangPathWatcherInterface &operator=(const ClangPathWatcherInterface &) = delete;
 
     virtual void updateIdPaths(const std::vector<IdPaths> &idPaths) = 0;
-    virtual void removeIds(const Utils::SmallStringVector &ids) = 0;
+    virtual void removeIds(const ProjectPartIds &ids) = 0;
 
     virtual void setNotifier(ClangPathWatcherNotifier *notifier) = 0;
 
diff --git a/src/libs/clangsupport/clangpathwatchernotifier.h b/src/libs/clangsupport/clangpathwatchernotifier.h
index 188f11a8c2..393525dbf2 100644
--- a/src/libs/clangsupport/clangpathwatchernotifier.h
+++ b/src/libs/clangsupport/clangpathwatchernotifier.h
@@ -28,6 +28,7 @@
 #include "clangsupport_global.h"
 
 #include <filepathid.h>
+#include <projectpartid.h>
 
 #include <utils/smallstringvector.h>
 
@@ -40,7 +41,7 @@ public:
     ClangPathWatcherNotifier(const ClangPathWatcherNotifier &) = delete;
     ClangPathWatcherNotifier &operator=(const ClangPathWatcherNotifier &) = delete;
 
-    virtual void pathsWithIdsChanged(const Utils::SmallStringVector &ids) = 0;
+    virtual void pathsWithIdsChanged(const ProjectPartIds &ids) = 0;
     virtual void pathsChanged(const FilePathIds &filePathIds) = 0;
 
 protected:
diff --git a/src/libs/clangsupport/clangsupport-lib.pri b/src/libs/clangsupport/clangsupport-lib.pri
index 7ab8e47ac7..0668382803 100644
--- a/src/libs/clangsupport/clangsupport-lib.pri
+++ b/src/libs/clangsupport/clangsupport-lib.pri
@@ -52,7 +52,6 @@ SOURCES += \
     $$PWD/refactoringserverproxy.cpp \
     $$PWD/referencesmessage.cpp \
     $$PWD/unsavedfilesupdatedmessage.cpp \
-    $$PWD/removeprojectpartsmessage.cpp \
     $$PWD/requestannotationsmessage.cpp \
     $$PWD/requestfollowsymbolmessage.cpp \
     $$PWD/requestreferencesmessage.cpp \
@@ -87,6 +86,7 @@ SOURCES += \
     $$PWD/updategeneratedfilesmessage.cpp \
     $$PWD/removegeneratedfilesmessage.cpp \
     $$PWD/generatedfiles.cpp \
+    $$PWD/projectpartartefact.cpp \
     $$PWD/projectpartcontainer.cpp
 
 HEADERS += \
@@ -107,8 +107,12 @@ HEADERS += \
     $$PWD/clangrefactoringmessages.h \
     $$PWD/clangrefactoringservermessages.h \
     $$PWD/alivemessage.h \
+    $$PWD/clangsupportexceptions.h \
     $$PWD/completionsmessage.h \
     $$PWD/executeinloop.h \
+    $$PWD/projectpartid.h \
+    $$PWD/projectpartsstorage.h \
+    $$PWD/projectpartsstorageinterface.h \
     $$PWD/requestcompletionsmessage.h \
     $$PWD/echomessage.h \
     $$PWD/endmessage.h \
@@ -208,6 +212,7 @@ HEADERS += \
     $$PWD/progresscounter.h \
     $$PWD/includesearchpath.h \
     $$PWD/commandlinebuilder.h \
+    $$PWD/projectpartartefact.h \
     $$PWD/projectpartcontainer.h
 
 contains(QT_CONFIG, reduce_exports):CONFIG += hide_symbols
diff --git a/src/tools/clangrefactoringbackend/source/projectpartartefactexception.h b/src/libs/clangsupport/clangsupportexceptions.h
index 22f1b3ed94..05e48bea50 100644
--- a/src/tools/clangrefactoringbackend/source/projectpartartefactexception.h
+++ b/src/libs/clangsupport/clangsupportexceptions.h
@@ -1,6 +1,6 @@
 /****************************************************************************
 **
-** Copyright (C) 2017 The Qt Company Ltd.
+** Copyright (C) 2018 The Qt Company Ltd.
 ** Contact: https://www.qt.io/licensing/
 **
 ** This file is part of Qt Creator.
@@ -23,6 +23,8 @@
 **
 ****************************************************************************/
 
+#pragma once
+
 #include <sqliteexception.h>
 
 namespace ClangBackEnd {
@@ -30,11 +32,16 @@ namespace ClangBackEnd {
 class ProjectPartArtefactParseError : public Sqlite::Exception
 {
 public:
-    ProjectPartArtefactParseError(const char *whatErrorHasHappen,
-                                  Utils::SmallString &&errorMessage)
+    ProjectPartArtefactParseError(const char *whatErrorHasHappen, Utils::SmallString &&errorMessage)
         : Exception(whatErrorHasHappen, std::move(errorMessage))
-    {
-    }
+    {}
 };
 
-}
+class ProjectPartDoesNotExists : public Sqlite::Exception
+{
+public:
+    ProjectPartDoesNotExists(const char *whatErrorHasHappen, Utils::SmallString &&errorMessage)
+        : Exception(whatErrorHasHappen, std::move(errorMessage))
+    {}
+};
+} // namespace ClangBackEnd
diff --git a/src/libs/clangsupport/filepath.h b/src/libs/clangsupport/filepath.h
index 7207684194..b016b7de4f 100644
--- a/src/libs/clangsupport/filepath.h
+++ b/src/libs/clangsupport/filepath.h
@@ -95,6 +95,8 @@ public:
           m_slashIndex(std::ptrdiff_t(directory.size()))
     {}
 
+    bool isValid() const { return size() > 0 && m_slashIndex >= 0; }
+
     Utils::SmallStringView directory() const noexcept
     {
         return mid(0, std::size_t(std::max(std::ptrdiff_t(0), m_slashIndex)));
diff --git a/src/libs/clangsupport/filepathid.h b/src/libs/clangsupport/filepathid.h
index 88426d93fc..4feb06a531 100644
--- a/src/libs/clangsupport/filepathid.h
+++ b/src/libs/clangsupport/filepathid.h
@@ -40,6 +40,8 @@ class FilePathId
 public:
     constexpr FilePathId() = default;
 
+    FilePathId(const char *) = delete;
+
     FilePathId(int filePathId)
         : filePathId(filePathId)
     {}
diff --git a/src/libs/clangsupport/idpaths.h b/src/libs/clangsupport/idpaths.h
index 9fa06bdd4d..d67a73e83e 100644
--- a/src/libs/clangsupport/idpaths.h
+++ b/src/libs/clangsupport/idpaths.h
@@ -25,8 +25,7 @@
 
 #pragma once
 
-#include <utils/smallstring.h>
-
+#include "projectpartid.h"
 #include "filepathid.h"
 
 namespace ClangBackEnd {
@@ -34,7 +33,7 @@ namespace ClangBackEnd {
 class IdPaths
 {
 public:
-    Utils::SmallString id;
+    ProjectPartId id;
     FilePathIds filePathIds;
 
     friend bool operator==(const IdPaths &first, const IdPaths &second)
diff --git a/src/tools/clangrefactoringbackend/source/projectpartartefact.cpp b/src/libs/clangsupport/projectpartartefact.cpp
index 7623f38796..7623f38796 100644
--- a/src/tools/clangrefactoringbackend/source/projectpartartefact.cpp
+++ b/src/libs/clangsupport/projectpartartefact.cpp
diff --git a/src/tools/clangrefactoringbackend/source/projectpartartefact.h b/src/libs/clangsupport/projectpartartefact.h
index 505326c375..ac8c44a891 100644
--- a/src/tools/clangrefactoringbackend/source/projectpartartefact.h
+++ b/src/libs/clangsupport/projectpartartefact.h
@@ -25,7 +25,9 @@
 
 #pragma once
 
-#include "projectpartartefactexception.h"
+#include "clangsupport_global.h"
+#include "clangsupportexceptions.h"
+#include "projectpartid.h"
 
 #include <utils/cpplanguage_details.h>
 #include <utils/smallstringvector.h>
@@ -38,9 +40,28 @@ QT_FORWARD_DECLARE_STRUCT(QJsonParseError)
 
 namespace ClangBackEnd {
 
-class ProjectPartArtefact
+class CLANGSUPPORT_EXPORT ProjectPartArtefact
 {
 public:
+    ProjectPartArtefact() = default;
+    ProjectPartArtefact(ProjectPartId projectPartId,
+                        Utils::SmallStringVector &&toolChainArguments,
+                        CompilerMacros &&compilerMacros,
+                        IncludeSearchPaths &&systemIncludeSearchPaths,
+                        IncludeSearchPaths &&projectIncludeSearchPaths,
+                        Utils::Language language,
+                        Utils::LanguageVersion languageVersion,
+                        Utils::LanguageExtension languageExtension)
+        : projectPartId(projectPartId)
+        , toolChainArguments(std::move(toolChainArguments))
+        , compilerMacros(std::move(compilerMacros))
+        , systemIncludeSearchPaths(std::move(systemIncludeSearchPaths))
+        , projectIncludeSearchPaths(std::move(projectIncludeSearchPaths))
+        , language(language)
+        , languageVersion(languageVersion)
+        , languageExtension(languageExtension)
+    {}
+
     ProjectPartArtefact(Utils::SmallStringView compilerArgumentsText,
                         Utils::SmallStringView compilerMacrosText,
                         Utils::SmallStringView systemIncludeSearchPathsText,
@@ -49,11 +70,11 @@ public:
                         int language,
                         int languageVersion,
                         int languageExtension)
-        : toolChainArguments(toStringVector(compilerArgumentsText))
+        : projectPartId(projectPartId)
+        , toolChainArguments(toStringVector(compilerArgumentsText))
         , compilerMacros(toCompilerMacros(compilerMacrosText))
         , systemIncludeSearchPaths(toIncludeSearchPaths(systemIncludeSearchPathsText))
         , projectIncludeSearchPaths(toIncludeSearchPaths(projectIncludeSearchPathsText))
-        , projectPartId(projectPartId)
         , language(static_cast<Utils::Language>(language))
         , languageVersion(static_cast<Utils::LanguageVersion>(languageVersion))
         , languageExtension(static_cast<Utils::LanguageExtension>(languageExtension))
@@ -67,11 +88,11 @@ public:
                         Utils::Language language,
                         Utils::LanguageVersion languageVersion,
                         Utils::LanguageExtension languageExtension)
-        : toolChainArguments(toStringVector(compilerArgumentsText))
+        : projectPartId(projectPartId)
+        , toolChainArguments(toStringVector(compilerArgumentsText))
         , compilerMacros(toCompilerMacros(compilerMacrosText))
         , systemIncludeSearchPaths(toIncludeSearchPaths(systemIncludeSearchPathsText))
         , projectIncludeSearchPaths(toIncludeSearchPaths(projectIncludeSearchPathsText))
-        , projectPartId(projectPartId)
         , language(language)
         , languageVersion(languageVersion)
         , languageExtension(languageExtension)
@@ -87,11 +108,11 @@ public:
     friend bool operator==(const ProjectPartArtefact &first, const ProjectPartArtefact &second);
 
 public:
+    ProjectPartId projectPartId;
     Utils::SmallStringVector toolChainArguments;
     CompilerMacros compilerMacros;
     IncludeSearchPaths systemIncludeSearchPaths;
     IncludeSearchPaths projectIncludeSearchPaths;
-    int projectPartId = -1;
     Utils::Language language = Utils::Language::Cxx;
     Utils::LanguageVersion languageVersion = Utils::LanguageVersion::CXX98;
     Utils::LanguageExtension languageExtension = Utils::LanguageExtension::None;
diff --git a/src/libs/clangsupport/projectpartcontainer.cpp b/src/libs/clangsupport/projectpartcontainer.cpp
index a51e927db5..680b414dc7 100644
--- a/src/libs/clangsupport/projectpartcontainer.cpp
+++ b/src/libs/clangsupport/projectpartcontainer.cpp
@@ -29,12 +29,9 @@ namespace ClangBackEnd {
 
 QDebug operator<<(QDebug debug, const ProjectPartContainer &container)
 {
-    debug.nospace() << "ProjectPartContainer("
-                    << container.projectPartId << ","
-                    << container.toolChainArguments << ", "
-                    << container.headerPathIds << ", "
-                    << container.sourcePathIds
-                    << ")";
+    debug.nospace() << "ProjectPartContainer(" << container.projectPartId.projectPathId << ","
+                    << container.toolChainArguments << ", " << container.headerPathIds << ", "
+                    << container.sourcePathIds << ")";
 
     return debug;
 }
diff --git a/src/libs/clangsupport/projectpartcontainer.h b/src/libs/clangsupport/projectpartcontainer.h
index 0606591137..f1c64bd237 100644
--- a/src/libs/clangsupport/projectpartcontainer.h
+++ b/src/libs/clangsupport/projectpartcontainer.h
@@ -30,19 +30,21 @@
 #include "compilermacro.h"
 #include "filepathid.h"
 #include "includesearchpath.h"
+#include "projectpartartefact.h"
+#include "projectpartid.h"
 
 #include <utils/cpplanguage_details.h>
 #include <utils/smallstringio.h>
 
 namespace ClangBackEnd {
 
-class ProjectPartContainer
+class ProjectPartContainer : public ProjectPartArtefact
 {
     using uchar = unsigned char;
 public:
     ProjectPartContainer() = default;
-    ProjectPartContainer(Utils::SmallString &&projectPartId,
-                         Utils::SmallStringVector &&arguments,
+    ProjectPartContainer(ProjectPartId projectPartId,
+                         Utils::SmallStringVector &&toolChainArguments,
                          CompilerMacros &&compilerMacros,
                          IncludeSearchPaths &&systemIncludeSearchPaths,
                          IncludeSearchPaths &&projectIncludeSearchPaths,
@@ -51,18 +53,36 @@ public:
                          Utils::Language language,
                          Utils::LanguageVersion languageVersion,
                          Utils::LanguageExtension languageExtension)
-        : projectPartId(std::move(projectPartId))
-        , toolChainArguments(std::move(arguments))
-        , compilerMacros(std::move(compilerMacros))
-        , systemIncludeSearchPaths(std::move(systemIncludeSearchPaths))
-        , projectIncludeSearchPaths(std::move(projectIncludeSearchPaths))
+        : ProjectPartArtefact(projectPartId,
+                              std::move(toolChainArguments),
+                              std::move(compilerMacros),
+                              std::move(systemIncludeSearchPaths),
+                              std::move(projectIncludeSearchPaths),
+                              language,
+                              languageVersion,
+                              languageExtension)
         , headerPathIds(std::move(headerPathIds))
         , sourcePathIds(std::move(sourcePathIds))
-        , language(language)
-        , languageVersion(languageVersion)
-        , languageExtension(languageExtension)
-    {
-    }
+
+    {}
+
+    ProjectPartContainer(Utils::SmallStringView compilerArgumentsText,
+                         Utils::SmallStringView compilerMacrosText,
+                         Utils::SmallStringView systemIncludeSearchPathsText,
+                         Utils::SmallStringView projectIncludeSearchPathsText,
+                         int projectPartId,
+                         int language,
+                         int languageVersion,
+                         int languageExtension)
+        : ProjectPartArtefact(compilerArgumentsText,
+                              compilerMacrosText,
+                              systemIncludeSearchPathsText,
+                              projectIncludeSearchPathsText,
+                              projectPartId,
+                              language,
+                              languageVersion,
+                              languageExtension)
+    {}
 
     friend QDataStream &operator<<(QDataStream &out, const ProjectPartContainer &container)
     {
@@ -146,20 +166,14 @@ public:
     }
 
 public:
-    Utils::SmallString projectPartId;
-    Utils::SmallStringVector toolChainArguments;
-    CompilerMacros compilerMacros;
-    IncludeSearchPaths systemIncludeSearchPaths;
-    IncludeSearchPaths projectIncludeSearchPaths;
     FilePathIds headerPathIds;
     FilePathIds sourcePathIds;
-    Utils::Language language = Utils::Language::Cxx;
-    Utils::LanguageVersion languageVersion = Utils::LanguageVersion::CXX98;
-    Utils::LanguageExtension languageExtension = Utils::LanguageExtension::None;
     bool updateIsDeferred = false;
 };
 
+using ProjectPartContainerReference = std::reference_wrapper<ProjectPartContainer>;
 using ProjectPartContainers = std::vector<ProjectPartContainer>;
+using ProjectPartContainerReferences = std::vector<ProjectPartContainerReference>;
 
 CLANGSUPPORT_EXPORT QDebug operator<<(QDebug debug, const ProjectPartContainer &container);
 
diff --git a/src/libs/clangsupport/removeprojectpartsmessage.cpp b/src/libs/clangsupport/projectpartid.h
index d76d67cc40..c372682baf 100644
--- a/src/libs/clangsupport/removeprojectpartsmessage.cpp
+++ b/src/libs/clangsupport/projectpartid.h
@@ -1,6 +1,6 @@
 /****************************************************************************
 **
-** Copyright (C) 2016 The Qt Company Ltd.
+** Copyright (C) 2018 The Qt Company Ltd.
 ** Contact: https://www.qt.io/licensing/
 **
 ** This file is part of Qt Creator.
@@ -23,16 +23,55 @@
 **
 ****************************************************************************/
 
-#include "removeprojectpartsmessage.h"
+#pragma once
+
+#include <QDataStream>
 
 namespace ClangBackEnd {
 
-CLANGSUPPORT_EXPORT QDebug operator<<(QDebug debug, const RemoveProjectPartsMessage &message)
+class ProjectPartId
 {
-    debug.nospace() << "RemoveProjectPartsMessage("
-                    << message.projectsPartIds << ")";
+public:
+    constexpr ProjectPartId() = default;
+
+    ProjectPartId(const char *) = delete;
+
+    ProjectPartId(int projectPathId)
+        : projectPathId(projectPathId)
+    {}
+
+    bool isValid() const { return projectPathId >= 0; }
+
+    friend bool operator==(ProjectPartId first, ProjectPartId second)
+    {
+        return first.isValid() && first.projectPathId == second.projectPathId;
+    }
+
+    friend bool operator!=(ProjectPartId first, ProjectPartId second) { return !(first == second); }
+
+    friend bool operator<(ProjectPartId first, ProjectPartId second)
+    {
+        return first.projectPathId < second.projectPathId;
+    }
+
+    friend QDataStream &operator<<(QDataStream &out, const ProjectPartId &projectPathId)
+    {
+        out << projectPathId.projectPathId;
+
+        return out;
+    }
+
+    friend QDataStream &operator>>(QDataStream &in, ProjectPartId &projectPathId)
+    {
+        in >> projectPathId.projectPathId;
+
+        return in;
+    }
+
+public:
+    int projectPathId = -1;
+};
 
-    return debug;
-}
+using ProjectPartIds = std::vector<ProjectPartId>;
 
 } // namespace ClangBackEnd
diff --git a/src/libs/clangsupport/projectpartpch.cpp b/src/libs/clangsupport/projectpartpch.cpp
index 35ab29c799..aac672441c 100644
--- a/src/libs/clangsupport/projectpartpch.cpp
+++ b/src/libs/clangsupport/projectpartpch.cpp
@@ -29,8 +29,7 @@ namespace ClangBackEnd {
 
 QDebug operator<<(QDebug debug, const ProjectPartPch &projectPartPch)
 {
-    debug.nospace() << "FileContainer("
-                    << projectPartPch.projectPartId << ", "
+    debug.nospace() << "FileContainer(" << projectPartPch.projectPartId.projectPathId << ", "
                     << projectPartPch.pchPath << ")";
 
     return debug;
diff --git a/src/libs/clangsupport/projectpartpch.h b/src/libs/clangsupport/projectpartpch.h
index a413915b76..c471b46b16 100644
--- a/src/libs/clangsupport/projectpartpch.h
+++ b/src/libs/clangsupport/projectpartpch.h
@@ -27,8 +27,8 @@
 
 #include "clangsupport_global.h"
 
-#include <utils/smallstringio.h>
 #include <filepath.h>
+#include <projectpartid.h>
 
 namespace ClangBackEnd {
 
@@ -36,24 +36,28 @@ class ProjectPartPch
 {
 public:
     ProjectPartPch() = default;
-    ProjectPartPch(Utils::SmallString &&projectPartId,
-                   FilePath &&pchPath,
-                   long long lastModified)
-        : projectPartId(std::move(projectPartId)),
-          pchPath(std::move(pchPath)),
-          lastModified(lastModified)
+    ProjectPartPch(ProjectPartId projectPartId, FilePath &&pchPath, long long lastModified)
+        : projectPartId(projectPartId)
+        , pchPath(std::move(pchPath))
+        , lastModified(lastModified)
     {}
 
-    ProjectPartPch(Utils::SmallStringView pchPath,
-                   long long lastModified)
-        : pchPath(FilePathView(pchPath)),
-          lastModified(lastModified)
+    ProjectPartPch(int projectPartId, Utils::SmallStringView pchPath, long long lastModified)
+        : projectPartId(projectPartId)
+        , pchPath(FilePathView(pchPath))
+        , lastModified(lastModified)
     {}
 
+    bool isValid() const
+    {
+        return projectPartId.isValid() && pchPath.isValid() && lastModified >= 0;
+    }
+
     friend QDataStream &operator<<(QDataStream &out, const ProjectPartPch &container)
     {
         out << container.projectPartId;
         out << container.pchPath;
+        out << container.lastModified;
 
         return out;
     }
@@ -62,6 +66,7 @@ public:
     {
         in >> container.projectPartId;
         in >> container.pchPath;
+        in >> container.lastModified;
 
         return in;
     }
@@ -79,7 +84,7 @@ public:
     }
 
 public:
-    Utils::SmallString projectPartId;
+    ProjectPartId projectPartId;
     FilePath pchPath;
     long long lastModified = -1;
 };
diff --git a/src/libs/clangsupport/projectpartpchproviderinterface.h b/src/libs/clangsupport/projectpartpchproviderinterface.h
index 0b74bd6083..282e541cfd 100644
--- a/src/libs/clangsupport/projectpartpchproviderinterface.h
+++ b/src/libs/clangsupport/projectpartpchproviderinterface.h
@@ -39,7 +39,7 @@ public:
     ProjectPartPchProviderInterface &operator=(const ProjectPartPchProviderInterface &) = delete;
 
     virtual Utils::optional<ClangBackEnd::ProjectPartPch> projectPartPch(
-            Utils::SmallStringView projectPartId) const = 0;
+        ClangBackEnd::ProjectPartId projectPartId) const = 0;
     virtual const ClangBackEnd::ProjectPartPchs &projectPartPchs() const = 0;
 
 
diff --git a/src/libs/clangsupport/projectpartsstorage.h b/src/libs/clangsupport/projectpartsstorage.h
new file mode 100644
index 0000000000..c91291bca2
--- /dev/null
+++ b/src/libs/clangsupport/projectpartsstorage.h
@@ -0,0 +1,336 @@
+/****************************************************************************
+**
+** Copyright (C) 2018 The Qt Company Ltd.
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of Qt Creator.
+**
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and The Qt Company. For licensing terms
+** and conditions see https://www.qt.io/terms-conditions. For further
+** information use the contact form at https://www.qt.io/contact-us.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 3 as published by the Free Software
+** Foundation with exceptions as appearing in the file LICENSE.GPL3-EXCEPT
+** included in the packaging of this file. Please review the following
+** information to ensure the GNU General Public License requirements will
+** be met: https://www.gnu.org/licenses/gpl-3.0.html.
+**
+****************************************************************************/
+
+#pragma once
+
+#include "clangsupportexceptions.h"
+#include "projectpartsstorageinterface.h"
+
+#include <sqliteexception.h>
+#include <sqlitetransaction.h>
+
+namespace ClangBackEnd {
+
+template<typename Database = Sqlite::Database>
+class ProjectPartsStorage final : public ProjectPartsStorageInterface
+{
+    using ReadStatement = typename Database::ReadStatement;
+    using WriteStatement = typename Database::WriteStatement;
+
+public:
+    ProjectPartsStorage(Database &database)
+        : transaction(database)
+        , database(database)
+    {
+        transaction.commit();
+    }
+
+    ProjectPartContainers fetchProjectParts() const override
+    {
+        try {
+            Sqlite::DeferredTransaction transaction{database};
+
+            auto values = fetchProjectPartsStatement.template values<ProjectPartContainer, 8>(4096);
+
+            transaction.commit();
+
+            return values;
+        } catch (const Sqlite::StatementIsBusy &) {
+            return fetchProjectParts();
+        }
+    }
+
+    FilePathIds fetchHeaders(ProjectPartId projectPartId) const
+    {
+        return fetchProjectPartsHeadersByIdStatement
+            .template values<FilePathId>(1024, projectPartId.projectPathId);
+    }
+
+    FilePathIds fetchSources(ProjectPartId projectPartId) const
+    {
+        return fetchProjectPartsSourcesByIdStatement
+            .template values<FilePathId>(1024, projectPartId.projectPathId);
+    }
+
+    ProjectPartContainers fetchProjectParts(const ProjectPartIds &projectPartIds) const override
+    {
+        try {
+            ProjectPartContainers projectParts;
+            projectParts.reserve(projectPartIds.size());
+
+            Sqlite::DeferredTransaction transaction{database};
+
+            for (ProjectPartId projectPartId : projectPartIds) {
+                auto value = fetchProjectPartByIdStatement.template value<ProjectPartContainer, 8>(
+                    projectPartId.projectPathId);
+                if (value) {
+                    value->headerPathIds = fetchHeaders(projectPartId);
+                    value->sourcePathIds = fetchSources(projectPartId);
+                    projectParts.push_back(*std::move(value));
+                }
+            }
+
+            transaction.commit();
+
+            return projectParts;
+        } catch (const Sqlite::StatementIsBusy &) {
+            return fetchProjectParts(projectPartIds);
+        }
+    }
+
+    ProjectPartId fetchProjectPartId(Utils::SmallStringView projectPartName) const override
+    {
+        try {
+            Sqlite::DeferredTransaction transaction{database};
+
+            ProjectPartId projectPartId;
+            auto optionalProjectPartId = fetchProjectPartIdStatement.template value<ProjectPartId>(
+                projectPartName);
+
+            if (optionalProjectPartId) {
+                projectPartId = *optionalProjectPartId;
+            } else {
+                insertProjectPartNameStatement.write(projectPartName);
+
+                projectPartId = static_cast<int>(database.lastInsertedRowId());
+            }
+
+            transaction.commit();
+
+            return projectPartId;
+        } catch (const Sqlite::StatementIsBusy &) {
+            return fetchProjectPartId(projectPartName);
+        }
+    }
+
+    Utils::PathString fetchProjectPartName(ProjectPartId projectPartId) const
+    {
+        try {
+            Sqlite::DeferredTransaction transaction{database};
+
+            auto optionalProjectPartName = fetchProjectPartNameStatement.template value<Utils::PathString>(
+                projectPartId.projectPathId);
+
+            transaction.commit();
+
+            if (optionalProjectPartName)
+                return *std::move(optionalProjectPartName);
+        } catch (const Sqlite::StatementIsBusy &) {
+            return fetchProjectPartName(projectPartId);
+        }
+
+        throwProjectPartDoesNotExists(projectPartId);
+    }
+
+    void insertHeaders(ProjectPartId projectPartId, const FilePathIds &headerPathIds)
+    {
+        deleteProjectPartsHeadersByIdStatement.write(projectPartId.projectPathId);
+        for (FilePathId headerPathId : headerPathIds) {
+            insertProjectPartsHeadersStatement.write(projectPartId.projectPathId,
+                                                     headerPathId.filePathId);
+        }
+    }
+
+    void insertSources(ProjectPartId projectPartId, const FilePathIds &sourcePathIds)
+    {
+        deleteProjectPartsSourcesByIdStatement.write(projectPartId.projectPathId);
+        for (FilePathId sourcePathId : sourcePathIds) {
+            insertProjectPartsSourcesStatement.write(projectPartId.projectPathId,
+                                                     sourcePathId.filePathId);
+        }
+    }
+
+    void updateProjectPart(ProjectPartId projectPartId,
+                           const Utils::SmallStringVector &toolChainArguments,
+                           const CompilerMacros &compilerMacros,
+                           const IncludeSearchPaths &systemIncludeSearchPaths,
+                           const IncludeSearchPaths &projectIncludeSearchPaths,
+                           Utils::Language language,
+                           Utils::LanguageVersion languageVersion,
+                           Utils::LanguageExtension languageExtension) override
+    {
+        Utils::SmallString toolChainArgumentsAsJson = toJson(toolChainArguments);
+        Utils::SmallString compilerMacrosAsJson = toJson(compilerMacros);
+        Utils::SmallString systemIncludeSearchPathsAsJason = toJson(systemIncludeSearchPaths);
+        Utils::SmallString projectIncludeSearchPathsAsJason = toJson(projectIncludeSearchPaths);
+
+        updateProjectPartStatement.write(projectPartId.projectPathId,
+                                         toolChainArgumentsAsJson,
+                                         compilerMacrosAsJson,
+                                         systemIncludeSearchPathsAsJason,
+                                         projectIncludeSearchPathsAsJason,
+                                         static_cast<int>(language),
+                                         static_cast<int>(languageVersion),
+                                         static_cast<int>(languageExtension));
+    }
+
+    void updateProjectPart(const ProjectPartContainer &projectPart)
+    {
+        Utils::SmallString toolChainArgumentsAsJson = toJson(projectPart.toolChainArguments);
+        Utils::SmallString compilerMacrosAsJson = toJson(projectPart.compilerMacros);
+        Utils::SmallString systemIncludeSearchPathsAsJason = toJson(
+            projectPart.systemIncludeSearchPaths);
+        Utils::SmallString projectIncludeSearchPathsAsJason = toJson(
+            projectPart.projectIncludeSearchPaths);
+
+        updateProjectPartStatement.write(projectPart.projectPartId.projectPathId,
+                                         toolChainArgumentsAsJson,
+                                         compilerMacrosAsJson,
+                                         systemIncludeSearchPathsAsJason,
+                                         projectIncludeSearchPathsAsJason,
+                                         static_cast<int>(projectPart.language),
+                                         static_cast<int>(projectPart.languageVersion),
+                                         static_cast<int>(projectPart.languageExtension));
+
+        insertHeaders(projectPart.projectPartId, projectPart.headerPathIds);
+        insertSources(projectPart.projectPartId, projectPart.sourcePathIds);
+    }
+
+    void updateProjectParts(const ProjectPartContainers &projectParts) override
+    {
+        try {
+            Sqlite::ImmediateTransaction transaction{database};
+
+            for (const ProjectPartContainer &projectPart : projectParts)
+                updateProjectPart(projectPart);
+
+            transaction.commit();
+        } catch (const Sqlite::StatementIsBusy &) {
+            updateProjectParts(projectParts);
+        }
+    }
+
+    Utils::optional<ProjectPartArtefact> fetchProjectPartArtefact(FilePathId sourceId) const override
+    {
+        ReadStatement &statement = getProjectPartArtefactsBySourceId;
+
+        return statement.template value<ProjectPartArtefact, 8>(sourceId.filePathId);
+    }
+
+    Utils::optional<ProjectPartArtefact> fetchProjectPartArtefact(ProjectPartId projectPartId) const override
+    {
+        ReadStatement &statement = getProjectPartArtefactsByProjectPartId;
+
+        return statement.template value<ProjectPartArtefact, 8>(projectPartId.projectPathId);
+    }
+
+    Sqlite::TransactionInterface &transactionBackend() override { return database; }
+
+    static Utils::SmallString toJson(const Utils::SmallStringVector &strings)
+    {
+        QJsonDocument document;
+        QJsonArray array;
+
+        std::transform(strings.begin(),
+                       strings.end(),
+                       std::back_inserter(array),
+                       [](const auto &string) { return QJsonValue(string.data()); });
+
+        document.setArray(array);
+
+        return document.toJson(QJsonDocument::Compact);
+    }
+
+    static Utils::SmallString toJson(const CompilerMacros &compilerMacros)
+    {
+        QJsonDocument document;
+        QJsonArray array;
+
+        for (const CompilerMacro &macro : compilerMacros)
+            array.push_back(QJsonArray{{QString(macro.key), QString(macro.value), macro.index}});
+
+        document.setArray(array);
+
+        return document.toJson(QJsonDocument::Compact);
+    }
+
+    static Utils::SmallString toJson(const IncludeSearchPaths &includeSearchPaths)
+    {
+        QJsonDocument document;
+        QJsonArray array;
+
+        for (const IncludeSearchPath &path : includeSearchPaths)
+            array.push_back(QJsonArray{{path.path.data(), path.index, int(path.type)}});
+
+        document.setArray(array);
+
+        return document.toJson(QJsonDocument::Compact);
+    }
+
+    [[noreturn]] void throwProjectPartDoesNotExists(ProjectPartId projectPartId) const
+    {
+        throw ProjectPartDoesNotExists("Try to fetch non existing project part id: ",
+                                       Utils::SmallString::number(projectPartId.projectPathId));
+    }
+
+public:
+    Sqlite::ImmediateNonThrowingDestructorTransaction transaction;
+    Database &database;
+    mutable ReadStatement fetchProjectPartIdStatement{
+        "SELECT projectPartId FROM projectParts WHERE projectPartName = ?", database};
+    mutable WriteStatement insertProjectPartNameStatement{
+        "INSERT INTO projectParts(projectPartName) VALUES (?)", database};
+    mutable ReadStatement fetchProjectPartNameStatement{
+        "SELECT projectPartName FROM projectParts WHERE projectPartId = ?", database};
+    mutable ReadStatement fetchProjectPartsStatement{
+        "SELECT toolChainArguments, compilerMacros, systemIncludeSearchPaths, "
+        "projectIncludeSearchPaths, projectPartId, language, languageVersion, languageExtension "
+        "FROM projectParts",
+        database};
+    mutable ReadStatement fetchProjectPartByIdStatement{
+        "SELECT toolChainArguments, compilerMacros, systemIncludeSearchPaths, "
+        "projectIncludeSearchPaths, projectPartId, language, languageVersion, languageExtension "
+        "FROM projectParts WHERE projectPartId = ?",
+        database};
+    WriteStatement updateProjectPartStatement{
+        "UPDATE projectParts SET toolChainArguments=?002, compilerMacros=?003, "
+        "systemIncludeSearchPaths=?004, projectIncludeSearchPaths=?005, language=?006, "
+        "languageVersion=?007, languageExtension=?008 WHERE projectPartId = ?001",
+        database};
+    mutable ReadStatement getProjectPartArtefactsBySourceId{
+        "SELECT toolChainArguments, compilerMacros, systemIncludeSearchPaths, "
+        "projectIncludeSearchPaths, projectPartId, language, languageVersion, languageExtension "
+        "FROM projectParts WHERE projectPartId = (SELECT "
+        "projectPartId FROM projectPartsFiles WHERE sourceId = ?)",
+        database};
+    mutable ReadStatement getProjectPartArtefactsByProjectPartId{
+        "SELECT toolChainArguments, compilerMacros, systemIncludeSearchPaths, "
+        "projectIncludeSearchPaths, projectPartId, language, languageVersion, languageExtension "
+        "FROM projectParts WHERE projectPartId = ?",
+        database};
+    WriteStatement deleteProjectPartsHeadersByIdStatement{
+        "DELETE FROM projectPartsHeaders WHERE projectPartId = ?", database};
+    WriteStatement deleteProjectPartsSourcesByIdStatement{
+        "DELETE FROM projectPartsSources WHERE projectPartId = ?", database};
+    WriteStatement insertProjectPartsHeadersStatement{
+        "INSERT INTO projectPartsHeaders(projectPartId, sourceId) VALUES (?,?)", database};
+    WriteStatement insertProjectPartsSourcesStatement{
+        "INSERT INTO projectPartsSources(projectPartId, sourceId) VALUES (?,?)", database};
+    mutable ReadStatement fetchProjectPartsHeadersByIdStatement{
+        "SELECT sourceId FROM projectPartsHeaders WHERE projectPartId = ?", database};
+    mutable ReadStatement fetchProjectPartsSourcesByIdStatement{
+        "SELECT sourceId FROM projectPartsSources WHERE projectPartId = ?", database};
+};
+} // namespace ClangBackEnd
diff --git a/src/libs/clangsupport/projectpartsstorageinterface.h b/src/libs/clangsupport/projectpartsstorageinterface.h
new file mode 100644
index 0000000000..1127f70b1f
--- /dev/null
+++ b/src/libs/clangsupport/projectpartsstorageinterface.h
@@ -0,0 +1,73 @@
+/****************************************************************************
+**
+** Copyright (C) 2018 The Qt Company Ltd.
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of Qt Creator.
+**
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and The Qt Company. For licensing terms
+** and conditions see https://www.qt.io/terms-conditions. For further
+** information use the contact form at https://www.qt.io/contact-us.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 3 as published by the Free Software
+** Foundation with exceptions as appearing in the file LICENSE.GPL3-EXCEPT
+** included in the packaging of this file. Please review the following
+** information to ensure the GNU General Public License requirements will
+** be met: https://www.gnu.org/licenses/gpl-3.0.html.
+**
+****************************************************************************/
+
+#pragma once
+
+#include <projectpartcontainer.h>
+
+#include <sqlitetransaction.h>
+#include <utils/optional.h>
+#include <utils/smallstringview.h>
+
+#include <QJsonArray>
+#include <QJsonDocument>
+#include <QJsonObject>
+
+namespace ClangBackEnd {
+
+class ProjectPartsStorageInterface
+{
+public:
+    ProjectPartsStorageInterface() = default;
+    ProjectPartsStorageInterface(const ProjectPartsStorageInterface &) = delete;
+    ProjectPartsStorageInterface &operator=(const ProjectPartsStorageInterface &) = delete;
+
+    virtual ProjectPartContainers fetchProjectParts() const = 0;
+    virtual ProjectPartContainers fetchProjectParts(const ProjectPartIds &projectPartIds) const = 0;
+    virtual ProjectPartId fetchProjectPartId(Utils::SmallStringView projectPartName) const = 0;
+    virtual Utils::PathString fetchProjectPartName(ProjectPartId projectPartId) const = 0;
+    virtual void updateProjectPart(ProjectPartId projectPartId,
+                                   const Utils::SmallStringVector &commandLineArguments,
+                                   const CompilerMacros &compilerMacros,
+                                   const ClangBackEnd::IncludeSearchPaths &systemIncludeSearchPaths,
+                                   const ClangBackEnd::IncludeSearchPaths &projectIncludeSearchPaths,
+                                   Utils::Language language,
+                                   Utils::LanguageVersion languageVersion,
+                                   Utils::LanguageExtension languageExtension)
+        = 0;
+
+    virtual void updateProjectParts(const ProjectPartContainers &projectParts) = 0;
+
+    virtual Utils::optional<ProjectPartArtefact> fetchProjectPartArtefact(FilePathId sourceId) const = 0;
+    virtual Utils::optional<ProjectPartArtefact> fetchProjectPartArtefact(
+        ProjectPartId projectPartId) const = 0;
+
+    virtual Sqlite::TransactionInterface &transactionBackend() = 0;
+
+protected:
+    ~ProjectPartsStorageInterface() = default;
+};
+
+} // namespace ClangBackEnd
diff --git a/src/libs/clangsupport/refactoringdatabaseinitializer.h b/src/libs/clangsupport/refactoringdatabaseinitializer.h
index f6d64a81d3..efca925413 100644
--- a/src/libs/clangsupport/refactoringdatabaseinitializer.h
+++ b/src/libs/clangsupport/refactoringdatabaseinitializer.h
@@ -47,11 +47,13 @@ public:
             createSourcesTable();
             createDirectoriesTable();
             createProjectPartsTable();
-            createProjectPartsSourcesTable();
+            createProjectPartsFilesTable();
             createUsedMacrosTable();
             createFileStatusesTable();
             createSourceDependenciesTable();
             createPrecompiledHeadersTable();
+            createProjectPartsHeadersTable();
+            createProjectPartsSourcesTable();
 
             transaction.commit();
 
@@ -135,11 +137,11 @@ public:
         table.initialize(database);
     }
 
-    void createProjectPartsSourcesTable()
+    void createProjectPartsFilesTable()
     {
         Sqlite::Table table;
         table.setUseIfNotExists(true);
-        table.setName("projectPartsSources");
+        table.setName("projectPartsFiles");
         const Sqlite::Column &projectPartIdColumn = table.addColumn("projectPartId", Sqlite::ColumnType::Integer);
         const Sqlite::Column &sourceIdColumn = table.addColumn("sourceId", Sqlite::ColumnType::Integer);
         table.addColumn("sourceType", Sqlite::ColumnType::Integer);
@@ -203,6 +205,32 @@ public:
         table.initialize(database);
     }
 
+    void createProjectPartsHeadersTable()
+    {
+        Sqlite::Table table;
+        table.setUseIfNotExists(true);
+        table.setName("projectPartsHeaders");
+        const Sqlite::Column &projectPartIdColumn = table.addColumn("projectPartId",
+                                                                    Sqlite::ColumnType::Integer);
+        table.addColumn("sourceId", Sqlite::ColumnType::Integer);
+        table.addIndex({projectPartIdColumn});
+
+        table.initialize(database);
+    }
+
+    void createProjectPartsSourcesTable()
+    {
+        Sqlite::Table table;
+        table.setUseIfNotExists(true);
+        table.setName("projectPartsSources");
+        const Sqlite::Column &projectPartIdColumn = table.addColumn("projectPartId",
+                                                                    Sqlite::ColumnType::Integer);
+        table.addColumn("sourceId", Sqlite::ColumnType::Integer);
+        table.addIndex({projectPartIdColumn});
+
+        table.initialize(database);
+    }
+
 public:
     DatabaseType &database;
 };
diff --git a/src/libs/clangsupport/removeprojectpartsmessage.h b/src/libs/clangsupport/removeprojectpartsmessage.h
index 0aea092fea..ef80b52178 100644
--- a/src/libs/clangsupport/removeprojectpartsmessage.h
+++ b/src/libs/clangsupport/removeprojectpartsmessage.h
@@ -33,14 +33,11 @@ class RemoveProjectPartsMessage
 {
 public:
     RemoveProjectPartsMessage() = default;
-    RemoveProjectPartsMessage(Utils::SmallStringVector &&projectsPartIds)
+    RemoveProjectPartsMessage(ProjectPartIds &&projectsPartIds)
         : projectsPartIds(std::move(projectsPartIds))
     {}
 
-    Utils::SmallStringVector takeProjectsPartIds()
-    {
-        return std::move(projectsPartIds);
-    }
+    ProjectPartIds takeProjectsPartIds() { return std::move(projectsPartIds); }
 
     friend QDataStream &operator<<(QDataStream &out, const RemoveProjectPartsMessage &message)
     {
@@ -68,11 +65,9 @@ public:
     }
 
 public:
-    Utils::SmallStringVector projectsPartIds;
+    ProjectPartIds projectsPartIds;
 };
 
-CLANGSUPPORT_EXPORT QDebug operator<<(QDebug debug, const RemoveProjectPartsMessage &message);
-
 DECLARE_MESSAGE(RemoveProjectPartsMessage)
 
 } // namespace ClangBackEnd
diff --git a/src/plugins/clangpchmanager/clangpchmanagerplugin.cpp b/src/plugins/clangpchmanager/clangpchmanagerplugin.cpp
index 7d564399b6..cf5aae1bde 100644
--- a/src/plugins/clangpchmanager/clangpchmanagerplugin.cpp
+++ b/src/plugins/clangpchmanager/clangpchmanagerplugin.cpp
@@ -31,6 +31,7 @@
 #include "qtcreatorprojectupdater.h"
 
 #include <filepathcaching.h>
+#include <projectpartsstorage.h>
 #include <refactoringdatabaseinitializer.h>
 #include <sqlitedatabase.h>
 
@@ -79,11 +80,13 @@ public:
                                                      "Creating Dependencies");
             Core::ProgressManager::addTask(promise.future(), title, "dependency creation", nullptr);
         }};
+    ClangBackEnd::ProjectPartsStorage<Sqlite::Database> projectPartsStorage{database};
     PchManagerClient pchManagerClient{pchCreationProgressManager, dependencyCreationProgressManager};
     PchManagerConnectionClient connectionClient{&pchManagerClient};
     QtCreatorProjectUpdater<PchManagerProjectUpdater> projectUpdate{connectionClient.serverProxy(),
                                                                     pchManagerClient,
-                                                                    filePathCache};
+                                                                    filePathCache,
+                                                                    projectPartsStorage};
 };
 
 std::unique_ptr<ClangPchManagerPluginData> ClangPchManagerPlugin::d;
diff --git a/src/plugins/clangpchmanager/pchmanagerclient.cpp b/src/plugins/clangpchmanager/pchmanagerclient.cpp
index 4b0b5430d7..c26b871f50 100644
--- a/src/plugins/clangpchmanager/pchmanagerclient.cpp
+++ b/src/plugins/clangpchmanager/pchmanagerclient.cpp
@@ -44,10 +44,9 @@ void PchManagerClient::alive()
 void PchManagerClient::precompiledHeadersUpdated(ClangBackEnd::PrecompiledHeadersUpdatedMessage &&message)
 {
     for (ClangBackEnd::ProjectPartPch &projectPartPch : message.takeProjectPartPchs()) {
-        const QString projectPartId{projectPartPch.projectPartId};
         const QString pchPath{projectPartPch.pchPath};
         addProjectPartPch(std::move(projectPartPch));
-        precompiledHeaderUpdated(projectPartId, pchPath, projectPartPch.lastModified);
+        precompiledHeaderUpdated(projectPartPch.projectPartId, pchPath, projectPartPch.lastModified);
     }
 }
 
@@ -65,11 +64,10 @@ void PchManagerClient::progress(ClangBackEnd::ProgressMessage &&message)
     }
 }
 
-void PchManagerClient::precompiledHeaderRemoved(const QString &projectPartId)
+void PchManagerClient::precompiledHeaderRemoved(ClangBackEnd::ProjectPartId projectPartId)
 {
     for (auto notifier : m_notifiers) {
-        Utils::SmallString id(projectPartId);
-        removeProjectPartPch(id);
+        removeProjectPartPch(projectPartId);
         notifier->precompiledHeaderRemoved(projectPartId);
     }
 }
@@ -79,7 +77,8 @@ void PchManagerClient::setConnectionClient(PchManagerConnectionClient *connectio
     m_connectionClient = connectionClient;
 }
 
-Utils::optional<ClangBackEnd::ProjectPartPch> PchManagerClient::projectPartPch(Utils::SmallStringView projectPartId) const
+Utils::optional<ClangBackEnd::ProjectPartPch> PchManagerClient::projectPartPch(
+    ClangBackEnd::ProjectPartId projectPartId) const
 {
     auto found = std::lower_bound(m_projectPartPchs.cbegin(),
                                   m_projectPartPchs.cend(),
@@ -110,7 +109,7 @@ void PchManagerClient::detach(PchManagerNotifierInterface *notifierToBeDeleted)
     m_notifiers.erase(newEnd, m_notifiers.end());
 }
 
-void PchManagerClient::removeProjectPartPch(Utils::SmallStringView projectPartId)
+void PchManagerClient::removeProjectPartPch(ClangBackEnd::ProjectPartId projectPartId)
 {
     auto found = std::lower_bound(m_projectPartPchs.begin(),
                                   m_projectPartPchs.end(),
@@ -145,7 +144,7 @@ const std::vector<PchManagerNotifierInterface *> &PchManagerClient::notifiers()
     return m_notifiers;
 }
 
-void PchManagerClient::precompiledHeaderUpdated(const QString &projectPartId,
+void PchManagerClient::precompiledHeaderUpdated(ClangBackEnd::ProjectPartId projectPartId,
                                                 const QString &pchFilePath,
                                                 long long lastModified)
 {
diff --git a/src/plugins/clangpchmanager/pchmanagerclient.h b/src/plugins/clangpchmanager/pchmanagerclient.h
index ccbd03299a..308370356e 100644
--- a/src/plugins/clangpchmanager/pchmanagerclient.h
+++ b/src/plugins/clangpchmanager/pchmanagerclient.h
@@ -52,21 +52,20 @@ public:
     void precompiledHeadersUpdated(ClangBackEnd::PrecompiledHeadersUpdatedMessage &&message) override;
     void progress(ClangBackEnd::ProgressMessage &&message) override;
 
-    void precompiledHeaderRemoved(const QString &projectPartId);
+    void precompiledHeaderRemoved(ClangBackEnd::ProjectPartId projectPartId);
 
     void setConnectionClient(PchManagerConnectionClient *connectionClient);
 
     Utils::optional<ClangBackEnd::ProjectPartPch> projectPartPch(
-            Utils::SmallStringView projectPartId) const override;
+        ClangBackEnd::ProjectPartId projectPartId) const override;
 
     const ClangBackEnd::ProjectPartPchs &projectPartPchs() const override
     {
         return m_projectPartPchs;
     }
 
-unittest_public:
-    const std::vector<PchManagerNotifierInterface*> &notifiers() const;
-    void precompiledHeaderUpdated(const QString &projectPartId,
+    unittest_public : const std::vector<PchManagerNotifierInterface *> &notifiers() const;
+    void precompiledHeaderUpdated(ClangBackEnd::ProjectPartId projectPartId,
                                   const QString &pchFilePath,
                                   long long lastModified);
 
@@ -74,7 +73,7 @@ unittest_public:
     void detach(PchManagerNotifierInterface *notifier);
 
     void addProjectPartPch(ClangBackEnd::ProjectPartPch &&projectPartPch);
-    void removeProjectPartPch(Utils::SmallStringView projectPartId);
+    void removeProjectPartPch(ClangBackEnd::ProjectPartId projectPartId);
 
 private:
     ClangBackEnd::ProjectPartPchs m_projectPartPchs;
diff --git a/src/plugins/clangpchmanager/pchmanagernotifierinterface.h b/src/plugins/clangpchmanager/pchmanagernotifierinterface.h
index 9f9b5d56cf..04461186d6 100644
--- a/src/plugins/clangpchmanager/pchmanagernotifierinterface.h
+++ b/src/plugins/clangpchmanager/pchmanagernotifierinterface.h
@@ -27,6 +27,8 @@
 
 #include "clangpchmanager_global.h"
 
+#include <projectpartid.h>
+
 QT_FORWARD_DECLARE_CLASS(QString)
 
 namespace ClangPchManager {
@@ -40,10 +42,11 @@ public:
     PchManagerNotifierInterface(const PchManagerNotifierInterface &) = delete;
     PchManagerNotifierInterface &operator=(const PchManagerNotifierInterface &) = delete;
 
-    virtual void precompiledHeaderUpdated(const QString &projectPartId,
+    virtual void precompiledHeaderUpdated(ClangBackEnd::ProjectPartId projectPartId,
                                           const QString &pchFilePath,
-                                          long long lastModified) = 0;
-    virtual void precompiledHeaderRemoved(const QString &projectPartId) = 0;
+                                          long long lastModified)
+        = 0;
+    virtual void precompiledHeaderRemoved(ClangBackEnd::ProjectPartId projectPartId) = 0;
 
     PchManagerClient &m_pchManagerClient;
 
diff --git a/src/plugins/clangpchmanager/pchmanagerprojectupdater.cpp b/src/plugins/clangpchmanager/pchmanagerprojectupdater.cpp
index f7b925049a..38af78719e 100644
--- a/src/plugins/clangpchmanager/pchmanagerprojectupdater.cpp
+++ b/src/plugins/clangpchmanager/pchmanagerprojectupdater.cpp
@@ -29,20 +29,22 @@
 
 namespace ClangPchManager {
 
-PchManagerProjectUpdater::PchManagerProjectUpdater(ClangBackEnd::ProjectManagementServerInterface &server,
-                                                   PchManagerClient &client,
-                                                   ClangBackEnd::FilePathCachingInterface &filePathCache)
-    : ProjectUpdater(server, filePathCache),
-      m_client(client)
+void PchManagerProjectUpdater::removeProjectParts(const ClangBackEnd::ProjectPartIds &projectPartIds)
 {
+    ProjectUpdater::removeProjectParts(projectPartIds);
+
+    for (ClangBackEnd::ProjectPartId projectPartId : projectPartIds)
+        m_client.precompiledHeaderRemoved(projectPartId);
 }
 
-void PchManagerProjectUpdater::removeProjectParts(const QStringList &projectPartIds)
+void PchManagerProjectUpdater::removeProjectParts(const QStringList &projectPartNames)
 {
+    ClangBackEnd::ProjectPartIds projectPartIds = toProjectPartIds(projectPartNames);
+
     ProjectUpdater::removeProjectParts(projectPartIds);
 
-    for (const QString &projectPartiId : projectPartIds)
-        m_client.precompiledHeaderRemoved(projectPartiId);
+    for (ClangBackEnd::ProjectPartId projectPartId : projectPartIds)
+        m_client.precompiledHeaderRemoved(projectPartId);
 }
 
 } // namespace ClangPchManager
diff --git a/src/plugins/clangpchmanager/pchmanagerprojectupdater.h b/src/plugins/clangpchmanager/pchmanagerprojectupdater.h
index 470e12fe4a..fd1b98eab4 100644
--- a/src/plugins/clangpchmanager/pchmanagerprojectupdater.h
+++ b/src/plugins/clangpchmanager/pchmanagerprojectupdater.h
@@ -34,9 +34,14 @@ class PchManagerProjectUpdater : public ProjectUpdater
 public:
     PchManagerProjectUpdater(ClangBackEnd::ProjectManagementServerInterface &server,
                              PchManagerClient &client,
-                             ClangBackEnd::FilePathCachingInterface &filePathCache);
+                             ClangBackEnd::FilePathCachingInterface &filePathCache,
+                             ClangBackEnd::ProjectPartsStorageInterface &projectPartsStorage)
+        : ProjectUpdater(server, filePathCache, projectPartsStorage)
+        , m_client(client)
+    {}
 
-    void removeProjectParts(const QStringList &projectPartIds);
+    void removeProjectParts(const ClangBackEnd::ProjectPartIds &projectPartIds);
+    void removeProjectParts(const QStringList &projectPartNames);
 
 private:
     PchManagerClient &m_client;
diff --git a/src/plugins/clangpchmanager/projectupdater.cpp b/src/plugins/clangpchmanager/projectupdater.cpp
index 4e5cf95017..fc8db5bc07 100644
--- a/src/plugins/clangpchmanager/projectupdater.cpp
+++ b/src/plugins/clangpchmanager/projectupdater.cpp
@@ -61,13 +61,6 @@ public:
     ClangBackEnd::FilePathIds sources;
 };
 
-ProjectUpdater::ProjectUpdater(ClangBackEnd::ProjectManagementServerInterface &server,
-                               ClangBackEnd::FilePathCachingInterface &filePathCache)
-    : m_server(server),
-    m_filePathCache(filePathCache)
-{
-}
-
 void ProjectUpdater::updateProjectParts(const std::vector<CppTools::ProjectPart *> &projectParts,
                                         Utils::SmallStringVector &&toolChainArguments)
 {
@@ -75,9 +68,9 @@ void ProjectUpdater::updateProjectParts(const std::vector<CppTools::ProjectPart
         toProjectPartContainers(projectParts), std::move(toolChainArguments)});
 }
 
-void ProjectUpdater::removeProjectParts(const QStringList &projectPartIds)
+void ProjectUpdater::removeProjectParts(ClangBackEnd::ProjectPartIds projectPartIds)
 {
-    Utils::SmallStringVector sortedIds(projectPartIds);
+    auto sortedIds{projectPartIds};
     std::sort(sortedIds.begin(), sortedIds.end());
 
     m_server.removeProjectParts(ClangBackEnd::RemoveProjectPartsMessage{std::move(sortedIds)});
@@ -278,7 +271,12 @@ ClangBackEnd::ProjectPartContainer ProjectUpdater::toProjectPartContainer(
 
     auto includeSearchPaths = createIncludeSearchPaths(*projectPart);
 
-    return ClangBackEnd::ProjectPartContainer(projectPart->id(),
+    const QByteArray projectPartName = projectPart->id().toUtf8();
+
+    ClangBackEnd::ProjectPartId projectPartId = m_projectPartsStorage.fetchProjectPartId(
+        projectPartName);
+
+    return ClangBackEnd::ProjectPartContainer(projectPartId,
                                               Utils::SmallStringVector(arguments),
                                               createCompilerMacros(projectPart->projectMacros),
                                               std::move(includeSearchPaths.system),
@@ -296,9 +294,6 @@ ClangBackEnd::ProjectPartContainers ProjectUpdater::toProjectPartContainers(
 {
     using namespace std::placeholders;
 
-    std::vector<ClangBackEnd::ProjectPartContainer> projectPartContainers;
-    projectPartContainers.reserve(projectParts.size());
-
     projectParts.erase(std::remove_if(projectParts.begin(),
                                       projectParts.end(),
                                       [](const CppTools::ProjectPart *projectPart) {
@@ -306,6 +301,9 @@ ClangBackEnd::ProjectPartContainers ProjectUpdater::toProjectPartContainers(
                                       }),
                        projectParts.end());
 
+    std::vector<ClangBackEnd::ProjectPartContainer> projectPartContainers;
+    projectPartContainers.reserve(projectParts.size());
+
     std::transform(projectParts.begin(),
                    projectParts.end(),
                    std::back_inserter(projectPartContainers),
@@ -336,4 +334,26 @@ ClangBackEnd::FilePaths ProjectUpdater::createExcludedPaths(
     return excludedPaths;
 }
 
+QString ProjectUpdater::fetchProjectPartName(ClangBackEnd::ProjectPartId projectPartId) const
+{
+    return m_projectPartsStorage.fetchProjectPartName(projectPartId).toQString();
+}
+
+ClangBackEnd::ProjectPartIds ProjectUpdater::toProjectPartIds(
+    const QStringList &projectPartNames) const
+{
+    ClangBackEnd::ProjectPartIds projectPartIds;
+    projectPartIds.reserve(projectPartIds.size());
+
+    std::transform(projectPartNames.begin(),
+                   projectPartNames.end(),
+                   std::back_inserter(projectPartIds),
+                   [&](const QString &projectPartName) {
+                       return m_projectPartsStorage.fetchProjectPartId(
+                           Utils::SmallString{projectPartName});
+                   });
+
+    return projectPartIds;
+}
+
 } // namespace ClangPchManager
diff --git a/src/plugins/clangpchmanager/projectupdater.h b/src/plugins/clangpchmanager/projectupdater.h
index 896a02def0..044b86f637 100644
--- a/src/plugins/clangpchmanager/projectupdater.h
+++ b/src/plugins/clangpchmanager/projectupdater.h
@@ -33,6 +33,7 @@
 #include <generatedfiles.h>
 #include <includesearchpath.h>
 #include <projectpartcontainer.h>
+#include <projectpartsstorageinterface.h>
 
 #include <projectexplorer/headerpath.h>
 
@@ -69,11 +70,16 @@ public:
     };
 
     ProjectUpdater(ClangBackEnd::ProjectManagementServerInterface &server,
-                   ClangBackEnd::FilePathCachingInterface &filePathCache);
+                   ClangBackEnd::FilePathCachingInterface &filePathCache,
+                   ClangBackEnd::ProjectPartsStorageInterface &projectPartsStorage)
+        : m_server(server)
+        , m_filePathCache(filePathCache)
+        , m_projectPartsStorage(projectPartsStorage)
+    {}
 
     void updateProjectParts(const std::vector<CppTools::ProjectPart *> &projectParts,
                             Utils::SmallStringVector &&toolChainArguments);
-    void removeProjectParts(const QStringList &projectPartIds);
+    void removeProjectParts(ClangBackEnd::ProjectPartIds projectPartIds);
 
     void updateGeneratedFiles(ClangBackEnd::V2::FileContainers &&generatedFiles);
     void removeGeneratedFiles(ClangBackEnd::FilePaths &&filePaths);
@@ -88,6 +94,7 @@ public:
             CppTools::ProjectPart *projectPart) const;
     ClangBackEnd::ProjectPartContainers toProjectPartContainers(
             std::vector<CppTools::ProjectPart *> projectParts) const;
+
     void addToHeaderAndSources(HeaderAndSources &headerAndSources,
                                const CppTools::ProjectFile &projectFile) const;
     static QStringList toolChainArguments(CppTools::ProjectPart *projectPart);
@@ -98,11 +105,16 @@ public:
     static ClangBackEnd::FilePaths createExcludedPaths(
             const ClangBackEnd::V2::FileContainers &generatedFiles);
 
+    QString fetchProjectPartName(ClangBackEnd::ProjectPartId projectPartId) const;
+
+    ClangBackEnd::ProjectPartIds toProjectPartIds(const QStringList &projectPartNames) const;
+
 private:
     ClangBackEnd::GeneratedFiles m_generatedFiles;
     ClangBackEnd::FilePaths m_excludedPaths;
     ClangBackEnd::ProjectManagementServerInterface &m_server;
     ClangBackEnd::FilePathCachingInterface &m_filePathCache;
+    ClangBackEnd::ProjectPartsStorageInterface &m_projectPartsStorage;
 };
 
 } // namespace ClangPchManager
diff --git a/src/plugins/clangpchmanager/qtcreatorprojectupdater.h b/src/plugins/clangpchmanager/qtcreatorprojectupdater.h
index 4d66a2f8c3..a53bbc678a 100644
--- a/src/plugins/clangpchmanager/qtcreatorprojectupdater.h
+++ b/src/plugins/clangpchmanager/qtcreatorprojectupdater.h
@@ -55,11 +55,12 @@ class QtCreatorProjectUpdater : public ProjectUpdaterType,
                                 public ProjectExplorer::ExtraCompilerFactoryObserver
 {
 public:
-    template <typename ClientType>
+    template<typename ClientType>
     QtCreatorProjectUpdater(ClangBackEnd::ProjectManagementServerInterface &server,
                             ClientType &client,
-                            ClangBackEnd::FilePathCachingInterface &filePathCache)
-        : ProjectUpdaterType(server, client, filePathCache)
+                            ClangBackEnd::FilePathCachingInterface &filePathCache,
+                            ClangBackEnd::ProjectPartsStorageInterface &projectPartsStorage)
+        : ProjectUpdaterType(server, client, filePathCache, projectPartsStorage)
     {
         connectToCppModelManager();
     }
@@ -78,7 +79,7 @@ public:
     }
 
     void projectPartsRemoved(const QStringList &projectPartIds)
-    {
+    {    
         ProjectUpdaterType::removeProjectParts(projectPartIds);
     }
 
diff --git a/src/plugins/clangrefactoring/clangrefactoringplugin.cpp b/src/plugins/clangrefactoring/clangrefactoringplugin.cpp
index ea765bed5f..059eff4c78 100644
--- a/src/plugins/clangrefactoring/clangrefactoringplugin.cpp
+++ b/src/plugins/clangrefactoring/clangrefactoringplugin.cpp
@@ -36,6 +36,7 @@
 #include <clangpchmanager/clangpchmanagerplugin.h>
 #include <clangpchmanager/progressmanager.h>
 #include <clangsupport/refactoringdatabaseinitializer.h>
+#include <projectpartsstorage.h>
 
 #include <cpptools/cppmodelmanager.h>
 
@@ -61,6 +62,8 @@ namespace ClangRefactoring {
 
 namespace {
 
+using ClangPchManager::ClangPchManagerPlugin;
+
 QString backendProcessPath()
 {
     return Core::ICore::libexecPath()
@@ -91,14 +94,16 @@ public:
     ClangBackEnd::RefactoringConnectionClient connectionClient{&refactoringClient};
     QuerySqliteReadStatementFactory statementFactory{database};
     SymbolQuery<QuerySqliteReadStatementFactory> symbolQuery{statementFactory};
+    ClangBackEnd::ProjectPartsStorage<Sqlite::Database> projectPartsStorage{database};
     RefactoringEngine engine{connectionClient.serverProxy(), refactoringClient, filePathCache, symbolQuery};
     QtCreatorSearch qtCreatorSearch;
     QtCreatorClangQueryFindFilter qtCreatorfindFilter{connectionClient.serverProxy(),
                                                       qtCreatorSearch,
                                                       refactoringClient};
     QtCreatorRefactoringProjectUpdater projectUpdate{connectionClient.serverProxy(),
-                                                     ClangPchManager::ClangPchManagerPlugin::pchManagerClient(),
-                                                     filePathCache};
+                                                     ClangPchManagerPlugin::pchManagerClient(),
+                                                     filePathCache,
+                                                     projectPartsStorage};
 };
 
 ClangRefactoringPlugin::ClangRefactoringPlugin()
diff --git a/src/plugins/clangrefactoring/qtcreatorrefactoringprojectupdater.cpp b/src/plugins/clangrefactoring/qtcreatorrefactoringprojectupdater.cpp
index f3ca992620..dea3ccfeec 100644
--- a/src/plugins/clangrefactoring/qtcreatorrefactoringprojectupdater.cpp
+++ b/src/plugins/clangrefactoring/qtcreatorrefactoringprojectupdater.cpp
@@ -60,10 +60,16 @@ std::vector<ClangBackEnd::V2::FileContainer> createGeneratedFiles()
 }
 }
 
-QtCreatorRefactoringProjectUpdater::QtCreatorRefactoringProjectUpdater(ClangBackEnd::ProjectManagementServerInterface &server,
-                                                                       ClangPchManager::PchManagerClient &pchManagerClient,
-                                                                       ClangBackEnd::FilePathCachingInterface &filePathCache)
-    : RefactoringProjectUpdater(server, pchManagerClient, *cppModelManager(), filePathCache)
+QtCreatorRefactoringProjectUpdater::QtCreatorRefactoringProjectUpdater(
+    ClangBackEnd::ProjectManagementServerInterface &server,
+    ClangPchManager::PchManagerClient &pchManagerClient,
+    ClangBackEnd::FilePathCachingInterface &filePathCache,
+    ClangBackEnd::ProjectPartsStorageInterface &projectPartsStorage)
+    : RefactoringProjectUpdater(server,
+                                pchManagerClient,
+                                *cppModelManager(),
+                                filePathCache,
+                                projectPartsStorage)
 {
     connectToCppModelManager();
 }
diff --git a/src/plugins/clangrefactoring/qtcreatorrefactoringprojectupdater.h b/src/plugins/clangrefactoring/qtcreatorrefactoringprojectupdater.h
index 118c15b50c..85d635a3af 100644
--- a/src/plugins/clangrefactoring/qtcreatorrefactoringprojectupdater.h
+++ b/src/plugins/clangrefactoring/qtcreatorrefactoringprojectupdater.h
@@ -32,9 +32,11 @@ namespace ClangRefactoring {
 class QtCreatorRefactoringProjectUpdater final : public RefactoringProjectUpdater
 {
 public:
-    QtCreatorRefactoringProjectUpdater(ClangBackEnd::ProjectManagementServerInterface &server,
-                                       ClangPchManager::PchManagerClient &pchManagerClient,
-                                       ClangBackEnd::FilePathCachingInterface &filePathCache);
+    QtCreatorRefactoringProjectUpdater(
+        ClangBackEnd::ProjectManagementServerInterface &server,
+        ClangPchManager::PchManagerClient &pchManagerClient,
+        ClangBackEnd::FilePathCachingInterface &filePathCache,
+        ClangBackEnd::ProjectPartsStorageInterface &projectPartsStorage);
 
 private:
     void abstractEditorUpdated(const QString &filePath, const QByteArray &contents);
diff --git a/src/plugins/clangrefactoring/refactoringprojectupdater.cpp b/src/plugins/clangrefactoring/refactoringprojectupdater.cpp
index 99b028e522..8cfd5b942a 100644
--- a/src/plugins/clangrefactoring/refactoringprojectupdater.cpp
+++ b/src/plugins/clangrefactoring/refactoringprojectupdater.cpp
@@ -26,19 +26,22 @@
 #include "refactoringprojectupdater.h"
 
 #include <cpptools/cppmodelmanager.h>
+#include <projectpartsstorageinterface.h>
 
 namespace ClangRefactoring {
 
-void RefactoringProjectUpdater::precompiledHeaderUpdated(const QString &projectPartId,
+void RefactoringProjectUpdater::precompiledHeaderUpdated(ClangBackEnd::ProjectPartId projectPartId,
                                                          const QString &,
                                                          long long)
 {
-    auto projectPart = m_cppModelManager.projectPartForId(projectPartId);
+    const QString projectPartName = fetchProjectPartName(projectPartId);
+
+    auto projectPart = m_cppModelManager.projectPartForId(projectPartName);
     if (projectPart)
         updateProjectParts({projectPart.data()}, {});
 }
 
-void RefactoringProjectUpdater::precompiledHeaderRemoved(const QString &projectPartId)
+void RefactoringProjectUpdater::precompiledHeaderRemoved(ClangBackEnd::ProjectPartId projectPartId)
 {
     removeProjectParts({projectPartId});
 }
diff --git a/src/plugins/clangrefactoring/refactoringprojectupdater.h b/src/plugins/clangrefactoring/refactoringprojectupdater.h
index 8e2652cf23..a9559ef94e 100644
--- a/src/plugins/clangrefactoring/refactoringprojectupdater.h
+++ b/src/plugins/clangrefactoring/refactoringprojectupdater.h
@@ -39,18 +39,18 @@ public:
     RefactoringProjectUpdater(ClangBackEnd::ProjectManagementServerInterface &server,
                               ClangPchManager::PchManagerClient &pchManagerClient,
                               CppTools::CppModelManagerInterface &cppModelManager,
-                              ClangBackEnd::FilePathCachingInterface &filePathCache)
-        : ClangPchManager::ProjectUpdater(server, filePathCache),
-          ClangPchManager::PchManagerNotifierInterface(pchManagerClient),
-          m_cppModelManager(cppModelManager)
+                              ClangBackEnd::FilePathCachingInterface &filePathCache,
+                              ClangBackEnd::ProjectPartsStorageInterface &projectPartsStorage)
+        : ClangPchManager::ProjectUpdater(server, filePathCache, projectPartsStorage)
+        , ClangPchManager::PchManagerNotifierInterface(pchManagerClient)
+        , m_cppModelManager(cppModelManager)
     {
-
     }
 
-    void precompiledHeaderUpdated(const QString &projectPartId,
+    void precompiledHeaderUpdated(ClangBackEnd::ProjectPartId projectPartId,
                                   const QString &pchFilePath,
                                   long long lastModified) override;
-    void precompiledHeaderRemoved(const QString &projectPartId) override;
+    void precompiledHeaderRemoved(ClangBackEnd::ProjectPartId projectPartId) override;
 
 private:
     CppTools::CppModelManagerInterface &m_cppModelManager;
diff --git a/src/tools/clangpchmanagerbackend/clangpchmanagerbackendmain.cpp b/src/tools/clangpchmanagerbackend/clangpchmanagerbackendmain.cpp
index 3237aab2fb..b2a58b0d66 100644
--- a/src/tools/clangpchmanagerbackend/clangpchmanagerbackendmain.cpp
+++ b/src/tools/clangpchmanagerbackend/clangpchmanagerbackendmain.cpp
@@ -30,11 +30,12 @@
 #include <connectionserver.h>
 #include <environment.h>
 #include <executeinloop.h>
+#include <filepathcaching.h>
 #include <generatedfiles.h>
 #include <modifiedtimechecker.h>
 #include <pchcreator.h>
-#include <pchmanagerserver.h>
 #include <pchmanagerclientproxy.h>
+#include <pchmanagerserver.h>
 #include <pchtaskgenerator.h>
 #include <pchtaskqueue.h>
 #include <pchtasksmerger.h>
@@ -42,7 +43,7 @@
 #include <processormanager.h>
 #include <progresscounter.h>
 #include <projectpartsmanager.h>
-#include <filepathcaching.h>
+#include <projectpartsstorage.h>
 #include <refactoringdatabaseinitializer.h>
 #include <sqlitedatabase.h>
 #include <taskscheduler.h>
@@ -63,14 +64,15 @@ using namespace std::chrono_literals;
 
 using ClangBackEnd::ClangPathWatcher;
 using ClangBackEnd::ConnectionServer;
+using ClangBackEnd::FilePathCache;
+using ClangBackEnd::FilePathView;
 using ClangBackEnd::GeneratedFiles;
 using ClangBackEnd::PchCreator;
 using ClangBackEnd::PchManagerClientProxy;
 using ClangBackEnd::PchManagerServer;
 using ClangBackEnd::PrecompiledHeaderStorage;
 using ClangBackEnd::ProjectPartsManager;
-using ClangBackEnd::FilePathCache;
-using ClangBackEnd::FilePathView;
+using ClangBackEnd::ProjectPartsStorage;
 using ClangBackEnd::TimeStamp;
 
 class PchManagerApplication final : public QCoreApplication
@@ -179,7 +181,8 @@ struct Data // because we have a cycle dependency
     ClangBackEnd::FilePathCaching filePathCache{database};
     ClangPathWatcher<QFileSystemWatcher, QTimer> includeWatcher{filePathCache};
     ApplicationEnvironment environment;
-    ProjectPartsManager projectParts;
+    ProjectPartsStorage<> projectPartsStorage{database};
+    ProjectPartsManager projectParts{projectPartsStorage};
     GeneratedFiles generatedFiles;
     PchCreatorManager pchCreatorManager{generatedFiles,
                                         environment,
diff --git a/src/tools/clangpchmanagerbackend/source/builddependenciesprovider.cpp b/src/tools/clangpchmanagerbackend/source/builddependenciesprovider.cpp
index a2a7a813ac..bf00f39098 100644
--- a/src/tools/clangpchmanagerbackend/source/builddependenciesprovider.cpp
+++ b/src/tools/clangpchmanagerbackend/source/builddependenciesprovider.cpp
@@ -101,19 +101,15 @@ UsedMacros BuildDependenciesProvider::createUsedMacrosFromStorage(const SourceEn
     return usedMacros;
 }
 
-std::pair<SourceEntries, int>
-BuildDependenciesProvider::createSourceEntriesFromStorage(
-    const FilePathIds &sourcePathIds,
-    Utils::SmallStringView projectPartName) const {
+std::pair<SourceEntries, ProjectPartId> BuildDependenciesProvider::createSourceEntriesFromStorage(
+    const FilePathIds &sourcePathIds, ProjectPartId projectPartId) const
+{
     SourceEntries includes;
 
     Sqlite::DeferredTransaction transaction(m_transactionBackend);
 
-    int projectPartId = m_storage.fetchProjectPartId(projectPartName);
-
     for (FilePathId sourcePathId : sourcePathIds) {
-        SourceEntries entries =
-            m_storage.fetchDependSources(sourcePathId, projectPartId);
+        SourceEntries entries = m_storage.fetchDependSources(sourcePathId, projectPartId);
         SourceEntries mergedEntries = setUnion<SourceEntries>(includes, entries);
 
         includes = std::move(mergedEntries);
@@ -124,8 +120,9 @@ BuildDependenciesProvider::createSourceEntriesFromStorage(
     return {includes, projectPartId};
 }
 
-void BuildDependenciesProvider::storeBuildDependency(
-    const BuildDependency &buildDependency, int projectPartId) {
+void BuildDependenciesProvider::storeBuildDependency(const BuildDependency &buildDependency,
+                                                     ProjectPartId projectPartId)
+{
     Sqlite::ImmediateTransaction transaction(m_transactionBackend);
     m_storage.insertOrUpdateSources(buildDependency.sources, projectPartId);
     m_storage.insertOrUpdateFileStatuses(buildDependency.fileStatuses);
diff --git a/src/tools/clangpchmanagerbackend/source/builddependenciesprovider.h b/src/tools/clangpchmanagerbackend/source/builddependenciesprovider.h
index 2eb5210518..9700b83aa3 100644
--- a/src/tools/clangpchmanagerbackend/source/builddependenciesprovider.h
+++ b/src/tools/clangpchmanagerbackend/source/builddependenciesprovider.h
@@ -55,9 +55,9 @@ public:
 private:
     BuildDependency createBuildDependencyFromStorage(SourceEntries &&includes) const;
     UsedMacros createUsedMacrosFromStorage(const SourceEntries &includes) const;
-    std::pair<SourceEntries, int> createSourceEntriesFromStorage(
-        const FilePathIds &sourcePathIds, Utils::SmallStringView projectPartName) const;
-    void storeBuildDependency(const BuildDependency &buildDependency, int projectPartId);
+    std::pair<SourceEntries, ProjectPartId> createSourceEntriesFromStorage(
+        const FilePathIds &sourcePathIds, ProjectPartId projectPartId) const;
+    void storeBuildDependency(const BuildDependency &buildDependency, ProjectPartId projectPartId);
 
 private:
     BuildDependenciesStorageInterface &m_storage;
diff --git a/src/tools/clangpchmanagerbackend/source/builddependenciesstorage.h b/src/tools/clangpchmanagerbackend/source/builddependenciesstorage.h
index 3e6d00da3f..e7269dd0f9 100644
--- a/src/tools/clangpchmanagerbackend/source/builddependenciesstorage.h
+++ b/src/tools/clangpchmanagerbackend/source/builddependenciesstorage.h
@@ -53,17 +53,16 @@ public:
         transaction.commit();
     }
 
-    void insertOrUpdateSources(const SourceEntries &sourceEntries, int projectPartId) override
+    void insertOrUpdateSources(const SourceEntries &sourceEntries, ProjectPartId projectPartId) override
     {
-        deleteAllProjectPartsSourcesWithProjectPartNameStatement.write(
-            projectPartId);
+        deleteAllProjectPartsFilesWithProjectPartNameStatement.write(projectPartId.projectPathId);
 
         for (const SourceEntry &entry : sourceEntries) {
-            insertOrUpdateProjectPartsSourcesStatement.write(
-                entry.sourceId.filePathId,
-                projectPartId,
-                static_cast<uchar>(entry.sourceType),
-                static_cast<uchar>(entry.hasMissingIncludes));
+            insertOrUpdateProjectPartsFilesStatement.write(entry.sourceId.filePathId,
+                                                             projectPartId.projectPathId,
+                                                             static_cast<uchar>(entry.sourceType),
+                                                             static_cast<uchar>(
+                                                                 entry.hasMissingIncludes));
         }
     }
 
@@ -108,22 +107,22 @@ public:
         deleteNewSourceDependenciesStatement.execute();
     }
 
-    int fetchProjectPartId(Utils::SmallStringView projectPartName) override
+    ProjectPartId fetchProjectPartId(Utils::SmallStringView projectPartName) override
     {
-        auto projectPartId = fetchProjectPartIdStatement.template value<int>(projectPartName);
+        auto projectPartId = fetchProjectPartIdStatement.template value<ProjectPartId>(projectPartName);
 
         if (projectPartId)
-            return projectPartId.value();
+            return *projectPartId;
 
         insertProjectPartNameStatement.write(projectPartName);
 
         return static_cast<int>(database.lastInsertedRowId());
     }
 
-    SourceEntries fetchDependSources(FilePathId sourceId, int projectPartId) const override
+    SourceEntries fetchDependSources(FilePathId sourceId, ProjectPartId projectPartId) const override
     {
-        return fetchSourceDependenciesStatement.template values<SourceEntry, 4>(
-            300, sourceId.filePathId, projectPartId);
+        return fetchSourceDependenciesStatement
+            .template values<SourceEntry, 4>(300, sourceId.filePathId, projectPartId.projectPathId);
     }
 
     UsedMacros fetchUsedMacros(FilePathId sourceId) const override
@@ -131,13 +130,11 @@ public:
         return fetchUsedMacrosStatement.template values<UsedMacro, 2>(128, sourceId.filePathId);
     }
 
-    void updatePchCreationTimeStamp(
-        long long pchCreationTimeStamp,
-        Utils::SmallStringView projectPartName) override {
+    void updatePchCreationTimeStamp(long long pchCreationTimeStamp, ProjectPartId projectPartId) override
+    {
         Sqlite::ImmediateTransaction transaction{database};
 
-        updatePchCreationTimeStampStatement.write(pchCreationTimeStamp,
-                                                  projectPartName);
+        updatePchCreationTimeStampStatement.write(pchCreationTimeStamp, projectPartId.projectPathId);
 
         transaction.commit();
     }
@@ -243,8 +240,8 @@ public:
         "DELETE FROM newSourceDependencies",
         database
     };
-    WriteStatement insertOrUpdateProjectPartsSourcesStatement{
-        "INSERT INTO projectPartsSources(sourceId, projectPartId, "
+    WriteStatement insertOrUpdateProjectPartsFilesStatement{
+        "INSERT INTO projectPartsFiles(sourceId, projectPartId, "
         "sourceType, hasMissingIncludes) VALUES (?001, ?002, ?003, ?004) ON "
         "CONFLICT(sourceId, projectPartId) DO UPDATE SET sourceType = ?003, "
         "hasMissingIncludes = ?004",
@@ -255,7 +252,7 @@ public:
         "collectedDependencies WHERE sourceDependencies.sourceId == "
         "collectedDependencies.sourceId) SELECT sourceId, "
         "pchCreationTimeStamp, sourceType, hasMissingIncludes FROM "
-        "collectedDependencies NATURAL JOIN projectPartsSources WHERE "
+        "collectedDependencies NATURAL JOIN projectPartsFiles WHERE "
         "projectPartId = ? ORDER BY sourceId",
         database};
     mutable ReadStatement fetchProjectPartIdStatement{
@@ -269,11 +266,9 @@ public:
         database
     };
     WriteStatement updatePchCreationTimeStampStatement{
-        "UPDATE projectPartsSources SET pchCreationTimeStamp = ?001 WHERE "
-        "projectPartId = (SELECT "
-        "projectPartId FROM projectParts WHERE projectPartName = ?002)",
+        "UPDATE projectPartsFiles SET pchCreationTimeStamp = ?001 WHERE projectPartId = ?002",
         database};
-    WriteStatement deleteAllProjectPartsSourcesWithProjectPartNameStatement{
-        "DELETE FROM projectPartsSources WHERE projectPartId = ?", database};
+    WriteStatement deleteAllProjectPartsFilesWithProjectPartNameStatement{
+        "DELETE FROM projectPartsFiles WHERE projectPartId = ?", database};
 };
 }
diff --git a/src/tools/clangpchmanagerbackend/source/builddependenciesstorageinterface.h b/src/tools/clangpchmanagerbackend/source/builddependenciesstorageinterface.h
index 4edc47fce1..a56e88b1f2 100644
--- a/src/tools/clangpchmanagerbackend/source/builddependenciesstorageinterface.h
+++ b/src/tools/clangpchmanagerbackend/source/builddependenciesstorageinterface.h
@@ -30,6 +30,7 @@
 #include <builddependency.h>
 #include <filepathid.h>
 #include <filestatus.h>
+#include <projectpartid.h>
 #include <sourcedependency.h>
 #include <usedmacro.h>
 
@@ -44,20 +45,17 @@ public:
     BuildDependenciesStorageInterface(const BuildDependenciesStorageInterface &) = delete;
     BuildDependenciesStorageInterface &operator=(const BuildDependenciesStorageInterface &) = delete;
 
-    virtual void insertOrUpdateSources(const SourceEntries &sourceIds,
-                                       int projectPartId) = 0;
+    virtual void insertOrUpdateSources(const SourceEntries &sourceIds, ProjectPartId projectPartId) = 0;
     virtual void insertOrUpdateUsedMacros(const UsedMacros &usedMacros) = 0;
     virtual void
     insertOrUpdateFileStatuses(const FileStatuses &fileStatuses) = 0;
     virtual void insertOrUpdateSourceDependencies(const SourceDependencies &sourceDependencies) = 0;
     virtual long long fetchLowestLastModifiedTime(FilePathId sourceId) const = 0;
     virtual SourceEntries fetchDependSources(FilePathId sourceId,
-                                             int projectPartId) const = 0;
+                                             ProjectPartId projectPartId) const = 0;
     virtual UsedMacros fetchUsedMacros(FilePathId sourceId) const = 0;
-    virtual int fetchProjectPartId(Utils::SmallStringView projectPartName) = 0;
-    virtual void updatePchCreationTimeStamp(long long pchCreationTimeStamp,
-                                            Utils::SmallStringView projectPartName)
-        = 0;
+    virtual ProjectPartId fetchProjectPartId(Utils::SmallStringView projectPartName) = 0;
+    virtual void updatePchCreationTimeStamp(long long pchCreationTimeStamp, ProjectPartId projectPartId) = 0;
 
 protected:
     ~BuildDependenciesStorageInterface() = default;
diff --git a/src/tools/clangpchmanagerbackend/source/pchmanagerserver.cpp b/src/tools/clangpchmanagerbackend/source/pchmanagerserver.cpp
index 89ad912640..c1c12121aa 100644
--- a/src/tools/clangpchmanagerbackend/source/pchmanagerserver.cpp
+++ b/src/tools/clangpchmanagerbackend/source/pchmanagerserver.cpp
@@ -83,9 +83,9 @@ void PchManagerServer::removeProjectParts(RemoveProjectPartsMessage &&message)
 }
 
 namespace {
-Utils::SmallStringVector projectPartIds(const ProjectPartContainers &projectParts)
+ProjectPartIds projectPartIds(const ProjectPartContainers &projectParts)
 {
-    Utils::SmallStringVector ids;
+    ProjectPartIds ids;
     ids.reserve(projectParts.size());
 
     std::transform(projectParts.cbegin(),
@@ -118,7 +118,7 @@ void PchManagerServer::removeGeneratedFiles(RemoveGeneratedFilesMessage &&messag
     m_generatedFiles.remove(message.takeGeneratedFiles());
 }
 
-void PchManagerServer::pathsWithIdsChanged(const Utils::SmallStringVector &ids)
+void PchManagerServer::pathsWithIdsChanged(const ProjectPartIds &ids)
 {
     ArgumentsEntries entries = m_toolChainsArgumentsCache.arguments(ids);
 
diff --git a/src/tools/clangpchmanagerbackend/source/pchmanagerserver.h b/src/tools/clangpchmanagerbackend/source/pchmanagerserver.h
index 9cf8aa8321..cc9daa7aa4 100644
--- a/src/tools/clangpchmanagerbackend/source/pchmanagerserver.h
+++ b/src/tools/clangpchmanagerbackend/source/pchmanagerserver.h
@@ -57,7 +57,7 @@ public:
     void updateGeneratedFiles(UpdateGeneratedFilesMessage &&message) override;
     void removeGeneratedFiles(RemoveGeneratedFilesMessage &&message) override;
 
-    void pathsWithIdsChanged(const Utils::SmallStringVector &ids) override;
+    void pathsWithIdsChanged(const ProjectPartIds &ids) override;
     void pathsChanged(const FilePathIds &filePathIds) override;
 
     void setPchCreationProgress(int progress, int total);
diff --git a/src/tools/clangpchmanagerbackend/source/pchtask.h b/src/tools/clangpchmanagerbackend/source/pchtask.h
index 528d6e63f1..7d8879fcbd 100644
--- a/src/tools/clangpchmanagerbackend/source/pchtask.h
+++ b/src/tools/clangpchmanagerbackend/source/pchtask.h
@@ -30,6 +30,7 @@
 #include <compilermacro.h>
 #include <filepath.h>
 #include <includesearchpath.h>
+#include <projectpartid.h>
 
 #include <utils/smallstringvector.h>
 #include <utils/cpplanguage_details.h>
@@ -39,11 +40,11 @@ namespace ClangBackEnd {
 class PchTask
 {
 public:
-    PchTask(Utils::SmallString &&projectPartId,
+    PchTask(ProjectPartId projectPartId,
             FilePathIds &&includes,
             FilePathIds &&sources,
             CompilerMacros &&compilerMacros,
-            Utils::SmallStringVector &&usedMacros,
+            Utils::SmallStringVector &&usedMacros, // TODO remove
             Utils::SmallStringVector toolChainArguments,
             IncludeSearchPaths systemIncludeSearchPaths,
             IncludeSearchPaths projectIncludeSearchPaths,
@@ -62,11 +63,11 @@ public:
         , languageExtension(languageExtension)
     {}
 
-    PchTask(Utils::SmallStringVector &&projectPartIds,
+    PchTask(ProjectPartIds &&projectPartIds,
             FilePathIds &&includes,
             FilePathIds &&sources,
             CompilerMacros &&compilerMacros,
-            Utils::SmallStringVector &&usedMacros,
+            Utils::SmallStringVector &&usedMacros, // TODO remove
             Utils::SmallStringVector toolChainArguments,
             IncludeSearchPaths systemIncludeSearchPaths,
             IncludeSearchPaths projectIncludeSearchPaths,
@@ -98,11 +99,11 @@ public:
                && first.languageExtension == second.languageExtension;
     }
 
-    Utils::SmallStringView projectPartId() const { return projectPartIds.front(); }
+    ProjectPartId projectPartId() const { return projectPartIds.front(); }
 
 public:
     FilePath systemPchPath;
-    Utils::SmallStringVector projectPartIds;
+    ProjectPartIds projectPartIds;
     FilePathIds includes;
     FilePathIds sources;
     CompilerMacros compilerMacros;
diff --git a/src/tools/clangpchmanagerbackend/source/pchtaskgenerator.cpp b/src/tools/clangpchmanagerbackend/source/pchtaskgenerator.cpp
index a44fc91b16..c0a42eae39 100644
--- a/src/tools/clangpchmanagerbackend/source/pchtaskgenerator.cpp
+++ b/src/tools/clangpchmanagerbackend/source/pchtaskgenerator.cpp
@@ -49,7 +49,7 @@ void PchTaskGenerator::addProjectParts(ProjectPartContainers &&projectParts,
                                buildDependency.usedMacros,
                                projectPart.compilerMacros};
 
-        pchTaskSets.emplace_back(PchTask{projectPart.projectPartId.clone(),
+        pchTaskSets.emplace_back(PchTask{projectPart.projectPartId,
                                          std::move(filter.topSystemIncludes),
                                          {},
                                          std::move(filter.systemCompilerMacros),
@@ -60,7 +60,7 @@ void PchTaskGenerator::addProjectParts(ProjectPartContainers &&projectParts,
                                          projectPart.language,
                                          projectPart.languageVersion,
                                          projectPart.languageExtension},
-                                 PchTask{std::move(projectPart.projectPartId),
+                                 PchTask{projectPart.projectPartId,
                                          std::move(filter.topProjectIncludes),
                                          std::move(filter.sources),
                                          std::move(filter.projectCompilerMacros),
@@ -77,7 +77,7 @@ void PchTaskGenerator::addProjectParts(ProjectPartContainers &&projectParts,
     m_pchTasksMergerInterface.mergeTasks(std::move(pchTaskSets), std::move(toolChainArguments));
 }
 
-void PchTaskGenerator::removeProjectParts(const Utils::SmallStringVector &projectsPartIds)
+void PchTaskGenerator::removeProjectParts(const ProjectPartIds &projectsPartIds)
 {
     m_pchTasksMergerInterface.removePchTasks(projectsPartIds);
 }
diff --git a/src/tools/clangpchmanagerbackend/source/pchtaskgenerator.h b/src/tools/clangpchmanagerbackend/source/pchtaskgenerator.h
index 38376ce2a2..dc7d201cde 100644
--- a/src/tools/clangpchmanagerbackend/source/pchtaskgenerator.h
+++ b/src/tools/clangpchmanagerbackend/source/pchtaskgenerator.h
@@ -50,8 +50,8 @@ public:
     {}
 
     void addProjectParts(ProjectPartContainers &&projectParts,
-                         Utils::SmallStringVector &&toolChainArguments);
-    void removeProjectParts(const Utils::SmallStringVector &projectsPartIds);
+                         Utils::SmallStringVector &&toolChainArguments) override;
+    void removeProjectParts(const ProjectPartIds &projectsPartIds) override;
 
 private:
     BuildDependenciesProviderInterface &m_buildDependenciesProvider;
diff --git a/src/tools/clangpchmanagerbackend/source/pchtaskgeneratorinterface.h b/src/tools/clangpchmanagerbackend/source/pchtaskgeneratorinterface.h
index 4546284265..abb25d2ef1 100644
--- a/src/tools/clangpchmanagerbackend/source/pchtaskgeneratorinterface.h
+++ b/src/tools/clangpchmanagerbackend/source/pchtaskgeneratorinterface.h
@@ -35,7 +35,7 @@ public:
     virtual void addProjectParts(ProjectPartContainers &&projectParts,
                                  Utils::SmallStringVector &&toolChainArguments)
         = 0;
-    virtual void removeProjectParts(const Utils::SmallStringVector &projectsPartIds) = 0;
+    virtual void removeProjectParts(const ProjectPartIds &projectsPartIds) = 0;
 
 protected:
     ~PchTaskGeneratorInterface() = default;
diff --git a/src/tools/clangpchmanagerbackend/source/pchtaskqueue.cpp b/src/tools/clangpchmanagerbackend/source/pchtaskqueue.cpp
index 6c1a09fd3e..2abe3fa394 100644
--- a/src/tools/clangpchmanagerbackend/source/pchtaskqueue.cpp
+++ b/src/tools/clangpchmanagerbackend/source/pchtaskqueue.cpp
@@ -54,18 +54,18 @@ void PchTaskQueue::addPchTasks(PchTasks &&newPchTasks, PchTasks &destination)
     m_progressCounter.addTotal(int(destination.size() - oldSize));
 }
 
-void PchTaskQueue::removePchTasksByProjectPartId(const Utils::SmallStringVector &projectsPartIds,
+void PchTaskQueue::removePchTasksByProjectPartId(const ProjectPartIds &projectsPartIds,
                                                  PchTasks &destination)
 {
     class CompareDifference
     {
     public:
-        bool operator()(const PchTask &first, const Utils::SmallString &second)
+        bool operator()(const PchTask &first, ProjectPartId second)
         {
             return first.projectPartId() < second;
         }
 
-        bool operator()(const Utils::SmallString &first, const PchTask &second)
+        bool operator()(ProjectPartId first, const PchTask &second)
         {
             return first < second.projectPartId();
         }
@@ -97,7 +97,7 @@ void PchTaskQueue::addProjectPchTasks(PchTasks &&pchTasks)
     addPchTasks(std::move(pchTasks), m_projectPchTasks);
 }
 
-void PchTaskQueue::removePchTasks(const Utils::SmallStringVector &projectsPartIds)
+void PchTaskQueue::removePchTasks(const ProjectPartIds &projectsPartIds)
 {
     removePchTasksByProjectPartId(projectsPartIds, m_projectPchTasks);
 }
diff --git a/src/tools/clangpchmanagerbackend/source/pchtaskqueue.h b/src/tools/clangpchmanagerbackend/source/pchtaskqueue.h
index 5d00419817..2d6d76ee58 100644
--- a/src/tools/clangpchmanagerbackend/source/pchtaskqueue.h
+++ b/src/tools/clangpchmanagerbackend/source/pchtaskqueue.h
@@ -56,7 +56,7 @@ public:
 
     void addSystemPchTasks(PchTasks &&pchTasks) override;
     void addProjectPchTasks(PchTasks &&pchTasks) override;
-    void removePchTasks(const Utils::SmallStringVector &projectsPartIds) override;
+    void removePchTasks(const ProjectPartIds &projectsPartIds) override;
 
     void processEntries() override;
 
@@ -68,8 +68,7 @@ public:
 
 private:
     void addPchTasks(PchTasks &&pchTasks, PchTasks &destination);
-    void removePchTasksByProjectPartId(const Utils::SmallStringVector &projectsPartIds,
-                                       PchTasks &destination);
+    void removePchTasksByProjectPartId(const ProjectPartIds &projectsPartIds, PchTasks &destination);
     void processProjectPchTasks();
     void processSystemPchTasks();
 
diff --git a/src/tools/clangpchmanagerbackend/source/pchtaskqueueinterface.h b/src/tools/clangpchmanagerbackend/source/pchtaskqueueinterface.h
index 45e1db8f9d..31c709d1a9 100644
--- a/src/tools/clangpchmanagerbackend/source/pchtaskqueueinterface.h
+++ b/src/tools/clangpchmanagerbackend/source/pchtaskqueueinterface.h
@@ -35,7 +35,7 @@ class PchTaskQueueInterface : public QueueInterface
 public:
     virtual void addSystemPchTasks(PchTasks &&pchTasks) = 0;
     virtual void addProjectPchTasks(PchTasks &&pchTasks) = 0;
-    virtual void removePchTasks(const Utils::SmallStringVector &projectsPartIds) = 0;
+    virtual void removePchTasks(const ProjectPartIds &projectsPartIds) = 0;
 
 protected:
     ~PchTaskQueueInterface() = default;
diff --git a/src/tools/clangpchmanagerbackend/source/pchtasksmerger.cpp b/src/tools/clangpchmanagerbackend/source/pchtasksmerger.cpp
index 65d1a3e9fe..7e850b8947 100644
--- a/src/tools/clangpchmanagerbackend/source/pchtasksmerger.cpp
+++ b/src/tools/clangpchmanagerbackend/source/pchtasksmerger.cpp
@@ -37,7 +37,7 @@ void PchTasksMerger::mergeTasks(PchTaskSets &&taskSets,
     m_pchTaskQueue.processEntries();
 }
 
-void PchTasksMerger::removePchTasks(const Utils::SmallStringVector &projectPartIds)
+void PchTasksMerger::removePchTasks(const ProjectPartIds &projectPartIds)
 {
     m_pchTaskQueue.removePchTasks(projectPartIds);
 }
diff --git a/src/tools/clangpchmanagerbackend/source/pchtasksmerger.h b/src/tools/clangpchmanagerbackend/source/pchtasksmerger.h
index 26df2022b4..5481a50dff 100644
--- a/src/tools/clangpchmanagerbackend/source/pchtasksmerger.h
+++ b/src/tools/clangpchmanagerbackend/source/pchtasksmerger.h
@@ -40,7 +40,7 @@ public:
     {}
 
     void mergeTasks(PchTaskSets &&taskSets, Utils::SmallStringVector &&toolChainArguments) override;
-    void removePchTasks(const Utils::SmallStringVector &projectPartIds) override;
+    void removePchTasks(const ProjectPartIds &projectPartIds) override;
 
     static CompilerMacros mergeMacros(const CompilerMacros &firstCompilerMacros,
                                       const CompilerMacros &secondCompilerMacros);
diff --git a/src/tools/clangpchmanagerbackend/source/pchtasksmergerinterface.h b/src/tools/clangpchmanagerbackend/source/pchtasksmergerinterface.h
index a691766b49..69f1e0470a 100644
--- a/src/tools/clangpchmanagerbackend/source/pchtasksmergerinterface.h
+++ b/src/tools/clangpchmanagerbackend/source/pchtasksmergerinterface.h
@@ -32,7 +32,7 @@ class PchTasksMergerInterface
 {
 public:
     virtual void mergeTasks(PchTaskSets &&taskSets, Utils::SmallStringVector &&toolChainArguments) = 0;
-    virtual void removePchTasks(const Utils::SmallStringVector &projectPartIds) = 0;
+    virtual void removePchTasks(const ProjectPartIds &projectPartIds) = 0;
 
 protected:
     ~PchTasksMergerInterface() = default;
diff --git a/src/tools/clangpchmanagerbackend/source/precompiledheaderstorage.h b/src/tools/clangpchmanagerbackend/source/precompiledheaderstorage.h
index 7d1069b998..e1b2f8aa2e 100644
--- a/src/tools/clangpchmanagerbackend/source/precompiledheaderstorage.h
+++ b/src/tools/clangpchmanagerbackend/source/precompiledheaderstorage.h
@@ -41,129 +41,125 @@ class PrecompiledHeaderStorage final : public PrecompiledHeaderStorageInterface
     using WriteStatement = typename Database::WriteStatement;
 public:
     PrecompiledHeaderStorage(Database &database)
-        : m_transaction(database),
-          m_database(database)
+        : transaction(database)
+        , database(database)
     {
-        m_transaction.commit();
+        transaction.commit();
     }
 
-    void insertProjectPrecompiledHeader(Utils::SmallStringView projectPartName,
+    void insertProjectPrecompiledHeader(ProjectPartId projectPartId,
                                         Utils::SmallStringView pchPath,
                                         long long pchBuildTime) override
     {
         try {
-            Sqlite::ImmediateTransaction transaction{m_database};
+            Sqlite::ImmediateTransaction transaction{database};
 
-            m_insertProjectPartStatement.write(projectPartName);
-            m_insertProjectPrecompiledHeaderStatement.write(projectPartName, pchPath, pchBuildTime);
+            insertProjectPrecompiledHeaderStatement.write(projectPartId.projectPathId,
+                                                          pchPath,
+                                                          pchBuildTime);
 
             transaction.commit();
-        } catch (const Sqlite::StatementIsBusy) {
-            insertProjectPrecompiledHeader(projectPartName, pchPath, pchBuildTime);
+        } catch (const Sqlite::StatementIsBusy &) {
+            insertProjectPrecompiledHeader(projectPartId, pchPath, pchBuildTime);
         }
     }
 
-    void deleteProjectPrecompiledHeader(Utils::SmallStringView projectPartName) override
+    void deleteProjectPrecompiledHeader(ProjectPartId projectPartId) override
     {
         try {
-            Sqlite::ImmediateTransaction transaction{m_database};
+            Sqlite::ImmediateTransaction transaction{database};
 
-            m_deleteProjectPrecompiledHeaderStatement.write(projectPartName);
+            deleteProjectPrecompiledHeaderStatement.write(projectPartId.projectPathId);
 
             transaction.commit();
         } catch (const Sqlite::StatementIsBusy) {
-            deleteProjectPrecompiledHeader(projectPartName);
+            deleteProjectPrecompiledHeader(projectPartId);
         }
     }
 
-    void insertSystemPrecompiledHeaders(const Utils::SmallStringVector &projectPartNames,
+    void insertSystemPrecompiledHeaders(const ProjectPartIds &projectPartIds,
                                         Utils::SmallStringView pchPath,
                                         long long pchBuildTime) override
     {
         try {
-            Sqlite::ImmediateTransaction transaction{m_database};
+            Sqlite::ImmediateTransaction transaction{database};
 
-            for (Utils::SmallStringView projectPartName : projectPartNames) {
-                m_insertProjectPartStatement.write(projectPartName);
-                m_insertSystemPrecompiledHeaderStatement.write(projectPartName, pchPath, pchBuildTime);
+            for (ProjectPartId projectPartId : projectPartIds) {
+                insertSystemPrecompiledHeaderStatement.write(projectPartId.projectPathId,
+                                                             pchPath,
+                                                             pchBuildTime);
             }
             transaction.commit();
         } catch (const Sqlite::StatementIsBusy) {
-            insertSystemPrecompiledHeaders(projectPartNames, pchPath, pchBuildTime);
+            insertSystemPrecompiledHeaders(projectPartIds, pchPath, pchBuildTime);
         }
     }
 
-    void deleteSystemPrecompiledHeaders(const Utils::SmallStringVector &projectPartNames) override
+    void deleteSystemPrecompiledHeaders(const ProjectPartIds &projectPartIds) override
     {
         try {
-            Sqlite::ImmediateTransaction transaction{m_database};
+            Sqlite::ImmediateTransaction transaction{database};
 
-            for (Utils::SmallStringView projectPartName : projectPartNames)
-                m_deleteSystemPrecompiledHeaderStatement.write(projectPartName);
+            for (ProjectPartId projectPartId : projectPartIds)
+                deleteSystemPrecompiledHeaderStatement.write(projectPartId.projectPathId);
 
             transaction.commit();
         } catch (const Sqlite::StatementIsBusy) {
-            deleteSystemPrecompiledHeaders(projectPartNames);
+            deleteSystemPrecompiledHeaders(projectPartIds);
         }
     }
 
-    FilePath fetchSystemPrecompiledHeaderPath(Utils::SmallStringView projectPartName) override
+    FilePath fetchSystemPrecompiledHeaderPath(ProjectPartId projectPartId) override
     {
         try {
-            Sqlite::DeferredTransaction transaction{m_database};
+            Sqlite::DeferredTransaction transaction{database};
 
-            auto value = m_fetchSystemPrecompiledHeaderPathStatement.template value<FilePath>(
-                projectPartName);
+            auto value = fetchSystemPrecompiledHeaderPathStatement.template value<FilePath>(
+                projectPartId.projectPathId);
 
             if (value)
-                return value.value();
+                return *value;
 
             transaction.commit();
         } catch (const Sqlite::StatementIsBusy) {
-            return fetchSystemPrecompiledHeaderPath(projectPartName);
+            return fetchSystemPrecompiledHeaderPath(projectPartId);
         }
 
         return FilePath("");
     }
 
-    Utils::optional<ProjectPartPch> fetchPrecompiledHeader(int projectPartId) const
+    Utils::optional<ProjectPartPch> fetchPrecompiledHeader(ProjectPartId projectPartId) const
     {
-        return m_getPrecompiledHeader.template value<ProjectPartPch, 2>(projectPartId);
+        return getPrecompiledHeader.template value<ProjectPartPch, 3>(projectPartId.projectPathId);
     }
 
 public:
-    Sqlite::ImmediateNonThrowingDestructorTransaction m_transaction;
-    Database &m_database;
-    WriteStatement m_insertProjectPrecompiledHeaderStatement{
+    Sqlite::ImmediateNonThrowingDestructorTransaction transaction;
+    Database &database;
+    WriteStatement insertProjectPrecompiledHeaderStatement{
         "INSERT INTO precompiledHeaders(projectPartId, projectPchPath, projectPchBuildTime) "
         "VALUES((SELECT projectPartId FROM projectParts WHERE projectPartName = ?001),?002,?003) "
         "ON CONFLICT (projectPartId) DO UPDATE SET projectPchPath=?002,projectPchBuildTime=?003",
-        m_database};
-    WriteStatement m_insertSystemPrecompiledHeaderStatement{
+        database};
+    WriteStatement insertSystemPrecompiledHeaderStatement{
         "INSERT INTO precompiledHeaders(projectPartId, systemPchPath, systemPchBuildTime) "
-        "VALUES((SELECT projectPartId FROM projectParts WHERE projectPartName = ?001),?002,?003) "
+        "VALUES(?001,?002,?003) "
         "ON CONFLICT (projectPartId) DO UPDATE SET systemPchPath=?002,systemPchBuildTime=?003",
-        m_database};
-    WriteStatement m_insertProjectPartStatement{
-        "INSERT OR IGNORE INTO projectParts(projectPartName) VALUES (?)", m_database};
-    WriteStatement m_deleteProjectPrecompiledHeaderStatement{
+        database};
+    WriteStatement deleteProjectPrecompiledHeaderStatement{
         "UPDATE OR IGNORE precompiledHeaders SET projectPchPath=NULL,projectPchBuildTime=NULL "
-        "WHERE projectPartId = (SELECT projectPartId FROM "
-        "projectParts WHERE projectPartName = ?)",
-        m_database};
-    WriteStatement m_deleteSystemPrecompiledHeaderStatement{
+        "WHERE projectPartId = ?",
+        database};
+    WriteStatement deleteSystemPrecompiledHeaderStatement{
         "UPDATE OR IGNORE precompiledHeaders SET systemPchPath=NULL,systemPchBuildTime=NULL "
-        "WHERE projectPartId = (SELECT projectPartId FROM "
-        "projectParts WHERE projectPartName = ?)",
-        m_database};
-    ReadStatement m_fetchSystemPrecompiledHeaderPathStatement{
-        "SELECT systemPchPath FROM precompiledHeaders WHERE projectPartId = (SELECT projectPartId "
-        "FROM projectParts WHERE projectPartName = ?)",
-        m_database};
-    mutable ReadStatement m_getPrecompiledHeader{
-        "SELECT ifnull(nullif(projectPchPath, ''), systemPchPath), "
+        "WHERE projectPartId = ?",
+        database};
+    ReadStatement fetchSystemPrecompiledHeaderPathStatement{
+        "SELECT systemPchPath FROM precompiledHeaders WHERE projectPartId = ?", database};
+    mutable ReadStatement getPrecompiledHeader{
+        "SELECT projectPartId, ifnull(nullif(projectPchPath, ''), systemPchPath), "
         "projectPchBuildTime FROM precompiledHeaders WHERE projectPartId = ?",
-        m_database};
+        database};
 };
 
 }
diff --git a/src/tools/clangpchmanagerbackend/source/precompiledheaderstorageinterface.h b/src/tools/clangpchmanagerbackend/source/precompiledheaderstorageinterface.h
index 06833be4a2..e2a2b4a3b6 100644
--- a/src/tools/clangpchmanagerbackend/source/precompiledheaderstorageinterface.h
+++ b/src/tools/clangpchmanagerbackend/source/precompiledheaderstorageinterface.h
@@ -28,6 +28,7 @@
 #include "projectpartpch.h"
 
 #include <filepath.h>
+#include <projectpartid.h>
 
 #include <utils/smallstringvector.h>
 #include <utils/optional.h>
@@ -42,18 +43,18 @@ public:
     PrecompiledHeaderStorageInterface(const PrecompiledHeaderStorageInterface &) = delete;
     PrecompiledHeaderStorageInterface &operator=(const PrecompiledHeaderStorageInterface &) = delete;
 
-    virtual void insertProjectPrecompiledHeader(Utils::SmallStringView projectPartName,
+    virtual void insertProjectPrecompiledHeader(ProjectPartId projectPartId,
                                                 Utils::SmallStringView pchPath,
                                                 long long pchBuildTime)
         = 0;
-    virtual void deleteProjectPrecompiledHeader(Utils::SmallStringView projectPartName) = 0;
-    virtual void insertSystemPrecompiledHeaders(const Utils::SmallStringVector &projectPartNames,
+    virtual void deleteProjectPrecompiledHeader(ProjectPartId projectPartName) = 0;
+    virtual void insertSystemPrecompiledHeaders(const ProjectPartIds &projectPartIds,
                                                 Utils::SmallStringView pchPath,
                                                 long long pchBuildTime)
         = 0;
-    virtual void deleteSystemPrecompiledHeaders(const Utils::SmallStringVector &projectPartNames) = 0;
-    virtual FilePath fetchSystemPrecompiledHeaderPath(Utils::SmallStringView projectPartName) = 0;
-    virtual Utils::optional<ProjectPartPch> fetchPrecompiledHeader(int projectPartId) const = 0;
+    virtual void deleteSystemPrecompiledHeaders(const ProjectPartIds &projectPartIds) = 0;
+    virtual FilePath fetchSystemPrecompiledHeaderPath(ProjectPartId projectPartId) = 0;
+    virtual Utils::optional<ProjectPartPch> fetchPrecompiledHeader(ProjectPartId projectPartId) const = 0;
 
 protected:
     ~PrecompiledHeaderStorageInterface() = default;
diff --git a/src/tools/clangpchmanagerbackend/source/projectpartsmanager.cpp b/src/tools/clangpchmanagerbackend/source/projectpartsmanager.cpp
index 8333ed9674..ada99f44cd 100644
--- a/src/tools/clangpchmanagerbackend/source/projectpartsmanager.cpp
+++ b/src/tools/clangpchmanagerbackend/source/projectpartsmanager.cpp
@@ -32,44 +32,115 @@
 namespace ClangBackEnd {
 
 inline namespace Pch {
+ProjectPartIds toProjectPartIds(const ProjectPartContainers &projectsParts)
+{
+    ProjectPartIds ids;
+    ids.reserve(projectsParts.size());
+    std::transform(projectsParts.begin(),
+                   projectsParts.end(),
+                   std::back_inserter(ids),
+                   [](const auto &projectPart) { return projectPart.projectPartId; });
+
+    return ids;
+}
 
 ProjectPartContainers ProjectPartsManager::update(ProjectPartContainers &&projectsParts)
 {
-    auto updatedProjectPartContainers = newProjectParts(std::move(projectsParts));
+    auto updatedProjectParts = filterNewProjectParts(std::move(projectsParts), m_projectParts);
 
-    mergeProjectParts(updatedProjectPartContainers);
+    if (updatedProjectParts.empty())
+        return {};
 
-    return updatedProjectPartContainers;
+    auto persistentProjectParts = m_projectPartsStorage.fetchProjectParts(
+        toProjectPartIds(updatedProjectParts));
+
+    if (persistentProjectParts.size() > 0) {
+        mergeProjectParts(persistentProjectParts);
+
+        updatedProjectParts = filterNewProjectParts(std::move(updatedProjectParts),
+                                                    persistentProjectParts);
+
+        if (updatedProjectParts.empty())
+            return {};
+    }
+
+    m_projectPartsStorage.updateProjectParts(updatedProjectParts);
+
+    mergeProjectParts(updatedProjectParts);
+
+    return updatedProjectParts;
 }
 
-void ProjectPartsManager::remove(const Utils::SmallStringVector &ids)
+void ProjectPartsManager::remove(const ProjectPartIds &projectPartIds)
 {
-    auto shouldRemove = [&] (const ProjectPartContainer &projectPart) {
-        return std::find(ids.begin(), ids.end(), projectPart.projectPartId) != ids.end();
+    ProjectPartContainers projectPartsWithoutIds;
+
+    struct Compare
+    {
+        bool operator()(ProjectPartId first, const ProjectPartContainer &second)
+        {
+            return first < second.projectPartId;
+        }
+
+        bool operator()(ProjectPartId first, const ProjectPartId &second) { return first < second; }
+
+        bool operator()(const ProjectPartContainer &first, const ProjectPartContainer &second)
+        {
+            return first.projectPartId < second.projectPartId;
+        }
+
+        bool operator()(const ProjectPartContainer &first, ProjectPartId second)
+        {
+            return first.projectPartId < second;
+        }
     };
 
-    auto newEnd = std::remove_if(m_projectParts.begin(), m_projectParts.end(), shouldRemove);
-    m_projectParts.erase(newEnd, m_projectParts.end());
+    std::set_difference(std::make_move_iterator(m_projectParts.begin()),
+                        std::make_move_iterator(m_projectParts.end()),
+                        projectPartIds.begin(),
+                        projectPartIds.end(),
+                        std::back_inserter(projectPartsWithoutIds),
+                        Compare{});
+
+    m_projectParts = std::move(projectPartsWithoutIds);
 }
 
-ProjectPartContainers ProjectPartsManager::projects(const Utils::SmallStringVector &projectPartIds) const
+ProjectPartContainers ProjectPartsManager::projects(const ProjectPartIds &projectPartIds) const
 {
     ProjectPartContainers projectPartsWithIds;
 
-    std::copy_if(m_projectParts.begin(),
-                 m_projectParts.end(),
-                 std::back_inserter(projectPartsWithIds),
-                 [&] (const ProjectPartContainer &projectPart) {
-        return std::binary_search(projectPartIds.begin(), projectPartIds.end(), projectPart.projectPartId);
-    });
+    struct Compare
+    {
+        bool operator()(ProjectPartId first, const ProjectPartContainer &second)
+        {
+            return first < second.projectPartId;
+        }
+
+        bool operator()(ProjectPartId first, const ProjectPartId &second) { return first < second; }
+
+        bool operator()(const ProjectPartContainer &first, const ProjectPartContainer &second)
+        {
+            return first.projectPartId < second.projectPartId;
+        }
+
+        bool operator()(const ProjectPartContainer &first, ProjectPartId second)
+        {
+            return first.projectPartId < second;
+        }
+    };
+
+    std::set_intersection(m_projectParts.begin(),
+                          m_projectParts.end(),
+                          projectPartIds.begin(),
+                          projectPartIds.end(),
+                          std::back_inserter(projectPartsWithIds),
+                          Compare{});
 
     return projectPartsWithIds;
 }
 
 void ProjectPartsManager::updateDeferred(const ProjectPartContainers &deferredProjectsParts)
 {
-    using ProjectPartContainerReferences = std::vector<std::reference_wrapper<ProjectPartContainer>>;
-
     ProjectPartContainerReferences deferredProjectPartPointers;
     deferredProjectPartPointers.reserve(deferredProjectsParts.size());
 
@@ -102,15 +173,16 @@ ProjectPartContainers ProjectPartsManager::deferredUpdates()
     return deferredProjectParts;
 }
 
-ProjectPartContainers ProjectPartsManager::newProjectParts(ProjectPartContainers &&projectsParts) const
+ProjectPartContainers ProjectPartsManager::filterNewProjectParts(
+    ProjectPartContainers &&projectsParts, const ProjectPartContainers &oldProjectParts)
 {
     ProjectPartContainers updatedProjectPartContainers;
     updatedProjectPartContainers.reserve(projectsParts.size());
 
     std::set_difference(std::make_move_iterator(projectsParts.begin()),
                         std::make_move_iterator(projectsParts.end()),
-                        m_projectParts.begin(),
-                        m_projectParts.end(),
+                        oldProjectParts.begin(),
+                        oldProjectParts.end(),
                         std::back_inserter(updatedProjectPartContainers));
 
     return updatedProjectPartContainers;
diff --git a/src/tools/clangpchmanagerbackend/source/projectpartsmanager.h b/src/tools/clangpchmanagerbackend/source/projectpartsmanager.h
index 2b3c43ebc8..6583db25c6 100644
--- a/src/tools/clangpchmanagerbackend/source/projectpartsmanager.h
+++ b/src/tools/clangpchmanagerbackend/source/projectpartsmanager.h
@@ -28,6 +28,7 @@
 #include "clangpchmanagerbackend_global.h"
 
 #include <projectpartsmanagerinterface.h>
+#include <projectpartsstorageinterface.h>
 
 #include <utils/smallstringvector.h>
 
@@ -37,18 +38,24 @@ inline namespace Pch {
 class ProjectPartsManager final : public ProjectPartsManagerInterface
 {
 public:
+    ProjectPartsManager(ProjectPartsStorageInterface &projectPartsStorage)
+        : m_projectPartsStorage(projectPartsStorage)
+    {}
+
     ProjectPartContainers update(ProjectPartContainers &&projectsParts) override;
-    void remove(const Utils::SmallStringVector &projectPartIds) override;
-    ProjectPartContainers projects(const Utils::SmallStringVector &projectPartIds) const override;
+    void remove(const ProjectPartIds &projectPartIds) override;
+    ProjectPartContainers projects(const ProjectPartIds &projectPartIds) const override;
     void updateDeferred(const ProjectPartContainers &projectsParts) override;
     ProjectPartContainers deferredUpdates() override;
 
-    ProjectPartContainers newProjectParts(ProjectPartContainers &&projectsParts) const;
+    static ProjectPartContainers filterNewProjectParts(ProjectPartContainers &&newProjectsParts,
+                                                       const ProjectPartContainers &oldProjectParts);
     void mergeProjectParts(const ProjectPartContainers &projectsParts);
     const ProjectPartContainers &projectParts() const;
 
 private:
     ProjectPartContainers m_projectParts;
+    ProjectPartsStorageInterface &m_projectPartsStorage;
 };
 
 } // namespace Pch
diff --git a/src/tools/clangpchmanagerbackend/source/projectpartsmanagerinterface.h b/src/tools/clangpchmanagerbackend/source/projectpartsmanagerinterface.h
index f99674ddda..ee80173f8a 100644
--- a/src/tools/clangpchmanagerbackend/source/projectpartsmanagerinterface.h
+++ b/src/tools/clangpchmanagerbackend/source/projectpartsmanagerinterface.h
@@ -37,10 +37,11 @@ public:
     ProjectPartsManagerInterface &operator=(const ProjectPartsManagerInterface &) = delete;
 
     virtual ProjectPartContainers update(ProjectPartContainers &&projectsParts) = 0;
-    virtual void remove(const Utils::SmallStringVector &projectPartIds) = 0;
-    virtual ProjectPartContainers projects(const Utils::SmallStringVector &projectPartIds) const = 0;
+    virtual void remove(const ProjectPartIds &projectPartIds) = 0;
+    virtual ProjectPartContainers projects(const ProjectPartIds &projectPartIds) const = 0;
     virtual void updateDeferred(const ProjectPartContainers &projectsParts) = 0;
     virtual ProjectPartContainers deferredUpdates() = 0;
+
 protected:
     ~ProjectPartsManagerInterface() = default;
 };
diff --git a/src/tools/clangpchmanagerbackend/source/toolchainargumentscache.h b/src/tools/clangpchmanagerbackend/source/toolchainargumentscache.h
index 4921b29a21..ed5ab3b1fd 100644
--- a/src/tools/clangpchmanagerbackend/source/toolchainargumentscache.h
+++ b/src/tools/clangpchmanagerbackend/source/toolchainargumentscache.h
@@ -33,19 +33,19 @@ namespace ClangBackEnd {
 
 struct ArgumentsEntry
 {
-    ArgumentsEntry(Utils::SmallStringVector &&ids, const Utils::SmallStringVector &arguments)
+    ArgumentsEntry(ProjectPartIds &&ids, const Utils::SmallStringVector &arguments)
         : ids(std::move(ids))
         , arguments(arguments)
     {}
 
-    ArgumentsEntry(const Utils::SmallStringVector &ids, const Utils::SmallStringVector &arguments)
+    ArgumentsEntry(ProjectPartIds &ids, const Utils::SmallStringVector &arguments)
         : ids(ids)
         , arguments(arguments)
     {}
 
-    void mergeIds(Utils::SmallStringVector &&newIds)
+    void mergeIds(ProjectPartIds &&newIds)
     {
-        Utils::SmallStringVector mergedIds;
+        ProjectPartIds mergedIds;
         mergedIds.reserve(ids.size() + newIds.size());
 
         std::set_union(std::make_move_iterator(ids.begin()),
@@ -54,12 +54,12 @@ struct ArgumentsEntry
                        std::make_move_iterator(newIds.end()),
                        std::back_inserter(mergedIds));
 
-        ids = mergedIds;
+        ids = std::move(mergedIds);
     }
 
-    void removeIds(const Utils::SmallStringVector &idsToBeRemoved)
+    void removeIds(const ProjectPartIds &idsToBeRemoved)
     {
-        Utils::SmallStringVector idsWithout;
+        ProjectPartIds idsWithout;
         idsWithout.reserve(ids.size());
         std::set_difference(std::make_move_iterator(ids.begin()),
                             std::make_move_iterator(ids.end()),
@@ -67,10 +67,10 @@ struct ArgumentsEntry
                             idsToBeRemoved.end(),
                             std::back_inserter(idsWithout));
 
-        ids = idsWithout;
+        ids = std::move(idsWithout);
     }
 
-    Utils::SmallStringVector ids;
+    ProjectPartIds ids;
     Utils::SmallStringVector arguments;
 };
 
@@ -118,11 +118,11 @@ public:
         removeEmptyEntries();
     }
 
-    void remove(const Utils::SmallStringVector &idsToBeRemoved)
+    void remove(const ProjectPartIds &idsToBeRemoved)
     {
         ArgumentsEntries entries;
         for (ArgumentsEntry &entry : m_argumentEntries) {
-            Utils::SmallStringVector usedIds;
+            ProjectPartIds usedIds;
             std::set_difference(entry.ids.begin(),
                                 entry.ids.end(),
                                 idsToBeRemoved.begin(),
@@ -135,11 +135,11 @@ public:
         removeEmptyEntries();
     }
 
-    ArgumentsEntries arguments(const Utils::SmallStringVector &ids) const
+    ArgumentsEntries arguments(const ProjectPartIds &ids) const
     {
         ArgumentsEntries entries;
         for (const ArgumentsEntry &entry : m_argumentEntries) {
-            Utils::SmallStringVector usedIds;
+            ProjectPartIds usedIds;
             std::set_intersection(entry.ids.begin(),
                                   entry.ids.end(),
                                   ids.begin(),
@@ -159,9 +159,9 @@ public:
     }
 
 private:
-    static Utils::SmallStringVector createIds(const ProjectPartContainers &projectParts)
+    static ProjectPartIds createIds(const ProjectPartContainers &projectParts)
     {
-        Utils::SmallStringVector ids;
+        ProjectPartIds ids;
         ids.reserve(projectParts.size());
         for (const auto &projectPart : projectParts)
             ids.emplace_back(projectPart.projectPartId);
@@ -181,7 +181,7 @@ private:
     }
 
 private:
-    std::vector<ArgumentsEntry> m_argumentEntries;
+    ArgumentsEntries m_argumentEntries;
 };
 
 }
diff --git a/src/tools/clangrefactoringbackend/source/clangrefactoringbackend-source.pri b/src/tools/clangrefactoringbackend/source/clangrefactoringbackend-source.pri
index fb1671aaf7..fcac51f226 100644
--- a/src/tools/clangrefactoringbackend/source/clangrefactoringbackend-source.pri
+++ b/src/tools/clangrefactoringbackend/source/clangrefactoringbackend-source.pri
@@ -17,8 +17,6 @@ HEADERS += \
     $$PWD/usedmacro.h \
     $$PWD/sourcedependency.h \
     $$PWD/filestatus.h \
-    $$PWD/projectpartartefactexception.h \
-    $$PWD/projectpartartefact.h \
     $$PWD/filestatuscache.h \
     $$PWD/indexdataconsumer.h \
     $$PWD/sourcesmanager.h \
@@ -68,5 +66,4 @@ HEADERS += \
 SOURCES += \
     $$PWD/sourcerangefilter.cpp \
     $$PWD/symbolindexer.cpp \
-    $$PWD/projectpartartefact.cpp \
     $$PWD/filestatuscache.cpp
diff --git a/src/tools/clangrefactoringbackend/source/collectmacrospreprocessorcallbacks.h b/src/tools/clangrefactoringbackend/source/collectmacrospreprocessorcallbacks.h
index 689e291098..1d16b0f5e1 100644
--- a/src/tools/clangrefactoringbackend/source/collectmacrospreprocessorcallbacks.h
+++ b/src/tools/clangrefactoringbackend/source/collectmacrospreprocessorcallbacks.h
@@ -209,7 +209,7 @@ public:
                     if (usr) {
                         m_symbolEntries.emplace(std::piecewise_construct,
                                                 std::forward_as_tuple(globalId),
-                                                std::forward_as_tuple(std::move(usr.value()),
+                                                std::forward_as_tuple(std::move(*usr),
                                                                       macroName,
                                                                       SymbolKind::Macro));
                     }
diff --git a/src/tools/clangrefactoringbackend/source/indexdataconsumer.cpp b/src/tools/clangrefactoringbackend/source/indexdataconsumer.cpp
index 35cc0df219..86e5fb597c 100644
--- a/src/tools/clangrefactoringbackend/source/indexdataconsumer.cpp
+++ b/src/tools/clangrefactoringbackend/source/indexdataconsumer.cpp
@@ -149,7 +149,7 @@ bool IndexDataConsumer::handleDeclOccurence(
                 auto  kindAndTags = symbolKindAndTags(declaration);
                 m_symbolEntries.emplace(std::piecewise_construct,
                                         std::forward_as_tuple(globalId),
-                                        std::forward_as_tuple(std::move(usr.value()),
+                                        std::forward_as_tuple(std::move(*usr),
                                                               symbolName(namedDeclaration),
                                                               kindAndTags.first,
                                                               kindAndTags.second));
diff --git a/src/tools/clangrefactoringbackend/source/symbolindexer.cpp b/src/tools/clangrefactoringbackend/source/symbolindexer.cpp
index aee8344fc9..e0315c6626 100644
--- a/src/tools/clangrefactoringbackend/source/symbolindexer.cpp
+++ b/src/tools/clangrefactoringbackend/source/symbolindexer.cpp
@@ -65,7 +65,8 @@ SymbolIndexer::SymbolIndexer(SymbolIndexerTaskQueueInterface &symbolIndexerTaskQ
                              ClangPathWatcherInterface &pathWatcher,
                              FilePathCachingInterface &filePathCache,
                              FileStatusCache &fileStatusCache,
-                             Sqlite::TransactionInterface &transactionInterface)
+                             Sqlite::TransactionInterface &transactionInterface,
+                             ProjectPartsStorageInterface &projectPartsStorage)
     : m_symbolIndexerTaskQueue(symbolIndexerTaskQueue)
     , m_symbolStorage(symbolStorage)
     , m_buildDependencyStorage(buildDependenciesStorage)
@@ -74,6 +75,7 @@ SymbolIndexer::SymbolIndexer(SymbolIndexerTaskQueueInterface &symbolIndexerTaskQ
     , m_filePathCache(filePathCache)
     , m_fileStatusCache(fileStatusCache)
     , m_transactionInterface(transactionInterface)
+    , m_projectPartsStorage(projectPartsStorage)
 {
     pathWatcher.setNotifier(this);
 }
@@ -86,26 +88,13 @@ void SymbolIndexer::updateProjectParts(ProjectPartContainers &&projectParts)
 
 void SymbolIndexer::updateProjectPart(ProjectPartContainer &&projectPart)
 {
-    Sqlite::ImmediateTransaction transaction{m_transactionInterface};
-    const auto optionalArtefact = m_symbolStorage.fetchProjectPartArtefact(projectPart.projectPartId);
-    int projectPartId = m_symbolStorage.insertOrUpdateProjectPart(
-        projectPart.projectPartId,
-        projectPart.toolChainArguments,
-        projectPart.compilerMacros,
-        projectPart.systemIncludeSearchPaths,
-        projectPart.projectIncludeSearchPaths,
-        projectPart.language,
-        projectPart.languageVersion,
-        projectPart.languageExtension);
-    if (optionalArtefact)
-        projectPartId = optionalArtefact->projectPartId;
+    Sqlite::DeferredTransaction transaction{m_transactionInterface};
+
+    ProjectPartId projectPartId = projectPart.projectPartId;
     const Utils::optional<ProjectPartPch> optionalProjectPartPch
         = m_precompiledHeaderStorage.fetchPrecompiledHeader(projectPartId);
 
-    FilePathIds sourcePathIds = updatableFilePathIds(projectPart, optionalArtefact);
     transaction.commit();
-    if (sourcePathIds.empty())
-        return;
 
     using Builder = CommandLineBuilder<ProjectPartContainer, Utils::SmallStringVector>;
     Builder commandLineBuilder{projectPart,
@@ -113,9 +102,8 @@ void SymbolIndexer::updateProjectPart(ProjectPartContainer &&projectPart)
                                InputFileType::Source,
                                {},
                                {},
-                               optionalProjectPartPch
-                                   ? FilePathView{optionalProjectPartPch.value().pchPath}
-                                   : FilePathView{}};
+                               optionalProjectPartPch ? FilePathView{optionalProjectPartPch->pchPath}
+                                                      : FilePathView{}};
 
     std::vector<SymbolIndexerTask> symbolIndexerTask;
     symbolIndexerTask.reserve(projectPart.sourcePathIds.size());
@@ -132,14 +120,6 @@ void SymbolIndexer::updateProjectPart(ProjectPartContainer &&projectPart)
 
                 m_symbolStorage.addSymbolsAndSourceLocations(symbolsCollector.symbols(),
                                                              symbolsCollector.sourceLocations());
-
-                m_buildDependencyStorage.insertOrUpdateUsedMacros(symbolsCollector.usedMacros());
-
-                m_buildDependencyStorage.insertOrUpdateFileStatuses(symbolsCollector.fileStatuses());
-
-                m_buildDependencyStorage.insertOrUpdateSourceDependencies(
-                    symbolsCollector.sourceDependencies());
-
                 transaction.commit();
             }
         };
@@ -151,9 +131,7 @@ void SymbolIndexer::updateProjectPart(ProjectPartContainer &&projectPart)
     m_symbolIndexerTaskQueue.processEntries();
 }
 
-void SymbolIndexer::pathsWithIdsChanged(const Utils::SmallStringVector &)
-{
-}
+void SymbolIndexer::pathsWithIdsChanged(const ProjectPartIds &) {}
 
 void SymbolIndexer::pathsChanged(const FilePathIds &filePathIds)
 {
@@ -173,8 +151,8 @@ void SymbolIndexer::updateChangedPath(FilePathId filePathId,
     m_fileStatusCache.update(filePathId);
 
     Sqlite::DeferredTransaction transaction{m_transactionInterface};
-    const Utils::optional<ProjectPartArtefact> optionalArtefact = m_symbolStorage.fetchProjectPartArtefact(
-        filePathId);
+    const Utils::optional<ProjectPartArtefact>
+        optionalArtefact = m_projectPartsStorage.fetchProjectPartArtefact(filePathId);
     if (!optionalArtefact)
         return;
 
@@ -182,9 +160,9 @@ void SymbolIndexer::updateChangedPath(FilePathId filePathId,
         = m_precompiledHeaderStorage.fetchPrecompiledHeader(optionalArtefact->projectPartId);
     transaction.commit();
 
-    const ProjectPartArtefact &artefact = optionalArtefact.value();
+    const ProjectPartArtefact &artefact = *optionalArtefact;
 
-    auto pchPath = optionalProjectPartPch ? optionalProjectPartPch.value().pchPath : FilePath{};
+    auto pchPath = optionalProjectPartPch ? optionalProjectPartPch->pchPath : FilePath{};
 
     CommandLineBuilder<ProjectPartArtefact, Utils::SmallStringVector>
         builder{artefact, artefact.toolChainArguments, InputFileType::Source, {}, {}, pchPath};
@@ -201,13 +179,6 @@ void SymbolIndexer::updateChangedPath(FilePathId filePathId,
             m_symbolStorage.addSymbolsAndSourceLocations(symbolsCollector.symbols(),
                                                          symbolsCollector.sourceLocations());
 
-            m_buildDependencyStorage.insertOrUpdateUsedMacros(symbolsCollector.usedMacros());
-
-            m_buildDependencyStorage.insertOrUpdateFileStatuses(symbolsCollector.fileStatuses());
-
-            m_buildDependencyStorage.insertOrUpdateSourceDependencies(
-                symbolsCollector.sourceDependencies());
-
             transaction.commit();
         }
     };
diff --git a/src/tools/clangrefactoringbackend/source/symbolindexer.h b/src/tools/clangrefactoringbackend/source/symbolindexer.h
index 33c691e4dd..c398c0f2bf 100644
--- a/src/tools/clangrefactoringbackend/source/symbolindexer.h
+++ b/src/tools/clangrefactoringbackend/source/symbolindexer.h
@@ -31,9 +31,10 @@
 #include "builddependenciesstorageinterface.h"
 #include "clangpathwatcher.h"
 
+#include <filecontainerv2.h>
 #include <precompiledheaderstorageinterface.h>
 #include <projectpartcontainer.h>
-#include <filecontainerv2.h>
+#include <projectpartsstorageinterface.h>
 
 namespace ClangBackEnd {
 
@@ -49,12 +50,13 @@ public:
                   ClangPathWatcherInterface &pathWatcher,
                   FilePathCachingInterface &filePathCache,
                   FileStatusCache &fileStatusCache,
-                  Sqlite::TransactionInterface &transactionInterface);
+                  Sqlite::TransactionInterface &transactionInterface,
+                  ProjectPartsStorageInterface &projectPartsStorage);
 
     void updateProjectParts(ProjectPartContainers &&projectParts);
     void updateProjectPart(ProjectPartContainer &&projectPart);
 
-    void pathsWithIdsChanged(const Utils::SmallStringVector &ids) override;
+    void pathsWithIdsChanged(const ProjectPartIds &ids) override;
     void pathsChanged(const FilePathIds &filePathIds) override;
     void updateChangedPath(FilePathId filePath,
                            std::vector<SymbolIndexerTask> &symbolIndexerTask);
@@ -78,6 +80,7 @@ private:
     FilePathCachingInterface &m_filePathCache;
     FileStatusCache &m_fileStatusCache;
     Sqlite::TransactionInterface &m_transactionInterface;
+    ProjectPartsStorageInterface &m_projectPartsStorage;
 };
 
 } // namespace ClangBackEnd
diff --git a/src/tools/clangrefactoringbackend/source/symbolindexertask.h b/src/tools/clangrefactoringbackend/source/symbolindexertask.h
index de3303815d..1695642522 100644
--- a/src/tools/clangrefactoringbackend/source/symbolindexertask.h
+++ b/src/tools/clangrefactoringbackend/source/symbolindexertask.h
@@ -26,6 +26,7 @@
 #pragma once
 
 #include <filepathid.h>
+#include <projectpartid.h>
 
 #include <functional>
 
@@ -43,12 +44,10 @@ class SymbolIndexerTask
 public:
     using Callable = std::function<void(SymbolsCollectorInterface &symbolsCollector)>;
 
-    SymbolIndexerTask(FilePathId filePathId,
-                      int projectPartId,
-                      Callable &&callable)
-        : callable(std::move(callable)),
-          filePathId(filePathId),
-          projectPartId(projectPartId)
+    SymbolIndexerTask(FilePathId filePathId, ProjectPartId projectPartId, Callable &&callable)
+        : callable(std::move(callable))
+        , filePathId(filePathId)
+        , projectPartId(projectPartId)
     {
     }
 
@@ -78,7 +77,7 @@ public:
 public:
     Callable callable;
     FilePathId filePathId;
-    int projectPartId;
+    ProjectPartId projectPartId;
 };
 
 } // namespace ClangBackEnd
diff --git a/src/tools/clangrefactoringbackend/source/symbolindexing.h b/src/tools/clangrefactoringbackend/source/symbolindexing.h
index 5b8b2221f0..c942059bad 100644
--- a/src/tools/clangrefactoringbackend/source/symbolindexing.h
+++ b/src/tools/clangrefactoringbackend/source/symbolindexing.h
@@ -36,6 +36,7 @@
 
 #include <builddependenciesstorage.h>
 #include <precompiledheaderstorage.h>
+#include <projectpartsstorage.h>
 
 #include <refactoringdatabaseinitializer.h>
 #include <filepathcachingfwd.h>
@@ -84,7 +85,8 @@ public:
                    ProgressCounter::SetProgressCallback &&setProgressCallback)
         : m_filePathCache(filePathCache)
         , m_buildDependencyStorage(database)
-        , m_recompiledHeaderStorage(database)
+        , m_precompiledHeaderStorage(database)
+        , m_projectPartsStorage(database)
         , m_symbolStorage(database)
         , m_collectorManger(generatedFiles, database)
         , m_progressCounter(std::move(setProgressCallback))
@@ -121,7 +123,8 @@ private:
     using SymbolIndexerTaskScheduler = TaskScheduler<SymbolsCollectorManager, SymbolIndexerTask::Callable>;
     FilePathCachingInterface &m_filePathCache;
     BuildDependenciesStorage m_buildDependencyStorage;
-    PrecompiledHeaderStorage<Sqlite::Database> m_recompiledHeaderStorage;
+    PrecompiledHeaderStorage<Sqlite::Database> m_precompiledHeaderStorage;
+    ProjectPartsStorage<Sqlite::Database> m_projectPartsStorage;
     SymbolStorage m_symbolStorage;
     ClangPathWatcher<QFileSystemWatcher, QTimer> m_sourceWatcher{m_filePathCache};
     FileStatusCache m_fileStatusCache{m_filePathCache};
@@ -130,11 +133,12 @@ private:
     SymbolIndexer m_indexer{m_indexerQueue,
                             m_symbolStorage,
                             m_buildDependencyStorage,
-                            m_recompiledHeaderStorage,
+                            m_precompiledHeaderStorage,
                             m_sourceWatcher,
                             m_filePathCache,
                             m_fileStatusCache,
-                            m_symbolStorage.m_database};
+                            m_symbolStorage.database,
+                            m_projectPartsStorage};
     SymbolIndexerTaskQueue m_indexerQueue{m_indexerScheduler, m_progressCounter};
     SymbolIndexerTaskScheduler m_indexerScheduler;
 };
diff --git a/src/tools/clangrefactoringbackend/source/symbolstorage.h b/src/tools/clangrefactoringbackend/source/symbolstorage.h
index 798fa26dd0..9dffe48c96 100644
--- a/src/tools/clangrefactoringbackend/source/symbolstorage.h
+++ b/src/tools/clangrefactoringbackend/source/symbolstorage.h
@@ -50,10 +50,10 @@ class SymbolStorage final : public SymbolStorageInterface
 
 public:
     SymbolStorage(Database &database)
-        : m_transaction(database),
-          m_database(database)
+        : transaction(database)
+        , database(database)
     {
-        m_transaction.commit();
+        transaction.commit();
     }
 
     void addSymbolsAndSourceLocations(const SymbolEntries &symbolEntries,
@@ -70,91 +70,9 @@ public:
         deleteNewLocationsTable();
     }
 
-    int insertOrUpdateProjectPart(Utils::SmallStringView projectPartName,
-                                  const Utils::SmallStringVector &toolChainArguments,
-                                  const CompilerMacros &compilerMacros,
-                                  const IncludeSearchPaths &systemIncludeSearchPaths,
-                                  const IncludeSearchPaths &projectIncludeSearchPaths,
-                                  Utils::Language language,
-                                  Utils::LanguageVersion languageVersion,
-                                  Utils::LanguageExtension languageExtension) override
-    {
-        Utils::SmallString toolChainArgumentsAsJson = toJson(toolChainArguments);
-        Utils::SmallString compilerMacrosAsJson = toJson(compilerMacros);
-        Utils::SmallString systemIncludeSearchPathsAsJason = toJson(systemIncludeSearchPaths);
-        Utils::SmallString projectIncludeSearchPathsAsJason = toJson(projectIncludeSearchPaths);
-
-        m_insertOrUpdateProjectPartStatement.write(projectPartName,
-                                                   toolChainArgumentsAsJson,
-                                                   compilerMacrosAsJson,
-                                                   systemIncludeSearchPathsAsJason,
-                                                   projectIncludeSearchPathsAsJason,
-                                                   static_cast<int>(language),
-                                                   static_cast<int>(languageVersion),
-                                                   static_cast<int>(languageExtension));
-
-        auto projectPartId = m_getProjectPartIdStatement.template value<int>(projectPartName);
-
-        return projectPartId.value();
-    }
-
-    Utils::optional<ProjectPartArtefact> fetchProjectPartArtefact(FilePathId sourceId) const override
-    {
-        ReadStatement &statement = m_getProjectPartArtefactsBySourceId;
-
-        return statement.template value<ProjectPartArtefact, 8>(sourceId.filePathId);
-    }
-
-    Utils::optional<ProjectPartArtefact> fetchProjectPartArtefact(Utils::SmallStringView projectPartName) const override
-    {
-        ReadStatement &statement = m_getProjectPartArtefactsByProjectPartName;
-
-        return statement.template value<ProjectPartArtefact, 8>(projectPartName);
-    }
-
-    static Utils::SmallString toJson(const Utils::SmallStringVector &strings)
-    {
-        QJsonDocument document;
-        QJsonArray array;
-
-        std::transform(strings.begin(), strings.end(), std::back_inserter(array), [] (const auto &string) {
-            return QJsonValue(string.data());
-        });
-
-        document.setArray(array);
-
-        return document.toJson(QJsonDocument::Compact);
-    }
-
-    static Utils::SmallString toJson(const CompilerMacros &compilerMacros)
-    {
-        QJsonDocument document;
-        QJsonArray array;
-
-        for (const CompilerMacro &macro : compilerMacros)
-            array.push_back(QJsonArray{{QString(macro.key), QString(macro.value), macro.index}});
-
-        document.setArray(array);
-
-        return document.toJson(QJsonDocument::Compact);
-    }
-
-    static Utils::SmallString toJson(const IncludeSearchPaths &includeSearchPaths)
-    {
-        QJsonDocument document;
-        QJsonArray array;
-
-        for (const IncludeSearchPath &path : includeSearchPaths)
-            array.push_back(QJsonArray{{path.path.data(), path.index, int(path.type)}});
-
-        document.setArray(array);
-
-        return document.toJson(QJsonDocument::Compact);
-    }
-
     void fillTemporarySymbolsTable(const SymbolEntries &symbolEntries)
     {
-        WriteStatement &statement = m_insertSymbolsToNewSymbolsStatement;
+        WriteStatement &statement = insertSymbolsToNewSymbolsStatement;
 
         for (const auto &symbolEntry : symbolEntries) {
             statement.write(symbolEntry.first,
@@ -166,7 +84,7 @@ public:
 
     void fillTemporaryLocationsTable(const SourceLocationEntries &sourceLocations)
     {
-        WriteStatement &statement = m_insertLocationsToNewLocationsStatement;
+        WriteStatement &statement = insertLocationsToNewLocationsStatement;
 
         for (const auto &locationEntry : sourceLocations) {
             statement.write(locationEntry.symbolId,
@@ -177,40 +95,22 @@ public:
         }
     }
 
-    void addNewSymbolsToSymbols()
-    {
-        m_addNewSymbolsToSymbolsStatement.execute();
-    }
+    void addNewSymbolsToSymbols() { addNewSymbolsToSymbolsStatement.execute(); }
 
-    void syncNewSymbolsFromSymbols()
-    {
-        m_syncNewSymbolsFromSymbolsStatement.execute();
-    }
+    void syncNewSymbolsFromSymbols() { syncNewSymbolsFromSymbolsStatement.execute(); }
 
-    void syncSymbolsIntoNewLocations()
-    {
-        m_syncSymbolsIntoNewLocationsStatement.execute();
-    }
+    void syncSymbolsIntoNewLocations() { syncSymbolsIntoNewLocationsStatement.execute(); }
 
     void deleteAllLocationsFromUpdatedFiles()
     {
-        m_deleteAllLocationsFromUpdatedFilesStatement.execute();
+        deleteAllLocationsFromUpdatedFilesStatement.execute();
     }
 
-    void insertNewLocationsInLocations()
-    {
-        m_insertNewLocationsInLocationsStatement.execute();
-    }
+    void insertNewLocationsInLocations() { insertNewLocationsInLocationsStatement.execute(); }
 
-    void deleteNewSymbolsTable()
-    {
-        m_deleteNewSymbolsTableStatement.execute();
-    }
+    void deleteNewSymbolsTable() { deleteNewSymbolsTableStatement.execute(); }
 
-    void deleteNewLocationsTable()
-    {
-        m_deleteNewLocationsTableStatement.execute();
-    }
+    void deleteNewLocationsTable() { deleteNewLocationsTableStatement.execute(); }
 
     SourceLocationEntries sourceLocations() const
     {
@@ -230,7 +130,7 @@ public:
         table.addIndex({usrColumn, symbolNameColumn});
         table.addIndex({symbolIdColumn});
 
-        table.initialize(m_database);
+        table.initialize(database);
 
         return table;
     }
@@ -248,85 +148,49 @@ public:
         table.addColumn("locationKind", Sqlite::ColumnType::Integer);
         table.addUniqueIndex({sourceIdColumn, lineColumn, columnColumn});
 
-        table.initialize(m_database);
+        table.initialize(database);
 
         return table;
     }
 
 public:
-    Sqlite::ImmediateNonThrowingDestructorTransaction m_transaction;
-    Database &m_database;
+    Sqlite::ImmediateNonThrowingDestructorTransaction transaction;
+    Database &database;
     Sqlite::Table newSymbolsTablet{createNewSymbolsTable()};
     Sqlite::Table newLocationsTable{createNewLocationsTable()};
-    WriteStatement m_insertSymbolsToNewSymbolsStatement{
+    WriteStatement insertSymbolsToNewSymbolsStatement{
         "INSERT INTO newSymbols(temporarySymbolId, usr, symbolName, symbolKind) VALUES(?,?,?,?)",
-        m_database};
-    WriteStatement m_insertLocationsToNewLocationsStatement{
-        "INSERT OR IGNORE INTO newLocations(temporarySymbolId, line, column, sourceId, locationKind) VALUES(?,?,?,?,?)",
-        m_database
-    };
-    ReadStatement m_selectNewSourceIdsStatement{
-        "SELECT DISTINCT sourceId FROM newLocations WHERE NOT EXISTS (SELECT sourceId FROM sources WHERE newLocations.sourceId == sources.sourceId)",
-        m_database
-    };
-    WriteStatement m_addNewSymbolsToSymbolsStatement{
+        database};
+    WriteStatement insertLocationsToNewLocationsStatement{
+        "INSERT OR IGNORE INTO newLocations(temporarySymbolId, line, column, sourceId, "
+        "locationKind) VALUES(?,?,?,?,?)",
+        database};
+    ReadStatement selectNewSourceIdsStatement{
+        "SELECT DISTINCT sourceId FROM newLocations WHERE NOT EXISTS (SELECT sourceId FROM sources "
+        "WHERE newLocations.sourceId == sources.sourceId)",
+        database};
+    WriteStatement addNewSymbolsToSymbolsStatement{
         "INSERT INTO symbols(usr, symbolName, symbolKind) "
         "SELECT usr, symbolName, symbolKind FROM newSymbols WHERE NOT EXISTS "
         "(SELECT usr FROM symbols WHERE symbols.usr == newSymbols.usr)",
-        m_database
-    };
-    WriteStatement m_syncNewSymbolsFromSymbolsStatement{
-        "UPDATE newSymbols SET symbolId = (SELECT symbolId FROM symbols WHERE newSymbols.usr = symbols.usr)",
-        m_database
-    };
-    WriteStatement m_syncSymbolsIntoNewLocationsStatement{
-        "UPDATE newLocations SET symbolId = (SELECT symbolId FROM newSymbols WHERE newSymbols.temporarySymbolId = newLocations.temporarySymbolId)",
-        m_database
-    };
-    WriteStatement m_deleteAllLocationsFromUpdatedFilesStatement{
+        database};
+    WriteStatement syncNewSymbolsFromSymbolsStatement{
+        "UPDATE newSymbols SET symbolId = (SELECT symbolId FROM symbols WHERE newSymbols.usr = "
+        "symbols.usr)",
+        database};
+    WriteStatement syncSymbolsIntoNewLocationsStatement{
+        "UPDATE newLocations SET symbolId = (SELECT symbolId FROM newSymbols WHERE "
+        "newSymbols.temporarySymbolId = newLocations.temporarySymbolId)",
+        database};
+    WriteStatement deleteAllLocationsFromUpdatedFilesStatement{
         "DELETE FROM locations WHERE sourceId IN (SELECT DISTINCT sourceId FROM newLocations)",
-        m_database
-    };
-    WriteStatement m_insertNewLocationsInLocationsStatement{
-        "INSERT INTO locations(symbolId, line, column, sourceId, locationKind) SELECT symbolId, line, column, sourceId, locationKind FROM newLocations",
-        m_database
-    };
-    WriteStatement m_deleteNewSymbolsTableStatement{
-        "DELETE FROM newSymbols",
-        m_database
-    };
-    WriteStatement m_deleteNewLocationsTableStatement{
-        "DELETE FROM newLocations",
-        m_database
-    };
-    WriteStatement m_insertOrUpdateProjectPartStatement{
-        "INSERT INTO projectParts(projectPartName, toolChainArguments, compilerMacros, "
-        "systemIncludeSearchPaths, projectIncludeSearchPaths, language, languageVersion, "
-        "languageExtension) VALUES (?001,?002,?003,?004,?005,?006,?007,?008) ON "
-        "CONFLICT(projectPartName) DO UPDATE SET toolChainArguments=?002, compilerMacros=?003, "
-        "systemIncludeSearchPaths=?004, projectIncludeSearchPaths=?005, language=?006, "
-        "languageVersion=?007, languageExtension=?008",
-        m_database};
-    mutable ReadStatement m_getProjectPartIdStatement{
-        "SELECT projectPartId FROM projectParts WHERE projectPartName = ?",
-        m_database
-    };
-
-    mutable ReadStatement m_getCompileArgumentsForFileIdStatement{
-        "SELECT toolChainArguments FROM projectParts WHERE projectPartId = (SELECT projectPartId "
-        "FROM projectPartsSources WHERE sourceId = ?)",
-        m_database};
-    mutable ReadStatement m_getProjectPartArtefactsBySourceId{
-        "SELECT toolChainArguments, compilerMacros, systemIncludeSearchPaths, "
-        "projectIncludeSearchPaths, projectPartId, language, languageVersion, languageExtension "
-        "FROM projectParts WHERE projectPartId = (SELECT "
-        "projectPartId FROM projectPartsSources WHERE sourceId = ?)",
-        m_database};
-    mutable ReadStatement m_getProjectPartArtefactsByProjectPartName{
-        "SELECT toolChainArguments, compilerMacros, systemIncludeSearchPaths, "
-        "projectIncludeSearchPaths, projectPartId, language, languageVersion, languageExtension "
-        "FROM projectParts WHERE projectPartName = ?",
-        m_database};
+        database};
+    WriteStatement insertNewLocationsInLocationsStatement{
+        "INSERT INTO locations(symbolId, line, column, sourceId, locationKind) SELECT symbolId, "
+        "line, column, sourceId, locationKind FROM newLocations",
+        database};
+    WriteStatement deleteNewSymbolsTableStatement{"DELETE FROM newSymbols", database};
+    WriteStatement deleteNewLocationsTableStatement{"DELETE FROM newLocations", database};
 };
 
 } // namespace ClangBackEnd
diff --git a/src/tools/clangrefactoringbackend/source/symbolstorageinterface.h b/src/tools/clangrefactoringbackend/source/symbolstorageinterface.h
index 210f66f7da..1d04c4d168 100644
--- a/src/tools/clangrefactoringbackend/source/symbolstorageinterface.h
+++ b/src/tools/clangrefactoringbackend/source/symbolstorageinterface.h
@@ -25,19 +25,13 @@
 
 #pragma once
 
-#include "filestatus.h"
-#include "projectpartentry.h"
-#include "projectpartartefact.h"
 #include "sourcelocationentry.h"
-#include "sourcedependency.h"
 #include "symbolentry.h"
-#include "usedmacro.h"
-
-#include <includesearchpath.h>
 
+#include <compilermacro.h>
 #include <sqlitetransaction.h>
 
-#include <compilermacro.h>
+#include <utils/cpplanguage_details.h>
 
 namespace ClangBackEnd {
 
@@ -51,20 +45,6 @@ public:
     virtual void addSymbolsAndSourceLocations(const SymbolEntries &symbolEntries,
                                               const SourceLocationEntries &sourceLocations)
         = 0;
-    virtual int insertOrUpdateProjectPart(
-        Utils::SmallStringView projectPartName,
-        const Utils::SmallStringVector &commandLineArguments,
-        const CompilerMacros &compilerMacros,
-        const ClangBackEnd::IncludeSearchPaths &systemIncludeSearchPaths,
-        const ClangBackEnd::IncludeSearchPaths &projectIncludeSearchPaths,
-        Utils::Language language,
-        Utils::LanguageVersion languageVersion,
-        Utils::LanguageExtension languageExtension)
-        = 0;
-    virtual Utils::optional<ProjectPartArtefact> fetchProjectPartArtefact(
-        FilePathId sourceId) const = 0;
-    virtual Utils::optional<ProjectPartArtefact> fetchProjectPartArtefact(
-        Utils::SmallStringView projectPartName) const = 0;
 
 protected:
     ~SymbolStorageInterface() = default;