libtracker-data: Inverse expectations when inserting a resource

Before this change we would first query the ID, and then insert it if non
existent. Apply the "better to ask for forgiveness than permission"
principle here, and try to always insert the resource. Only resort to
queries if there is a constraint violation (meaning the URI already
exists).

This optimizes insertions over lookups of existing resource IDs, but we
have other caching layers for the latter.

1 files changed, 40 insertions, 21 deletions

diff --git a/src/libtracker-data/tracker-data-update.c b/src/libtracker-data/tracker-data-update.c
index 378f434bc..a18bcff1c 100644
--- a/src/libtracker-data/tracker-data-update.c
+++ b/src/libtracker-data/tracker-data-update.c
@@ -785,38 +785,57 @@ ensure_resource_id (TrackerData *data,
 	GError *error = NULL;
 	gint id;
 
-	id = query_resource_id (data, uri);
+	id = GPOINTER_TO_INT (g_hash_table_lookup (data->update_buffer.resource_cache, uri));
 
-	if (create) {
-		*create = (id == 0);
+	if (id != 0) {
+		if (create)
+			*create = FALSE;
+		return id;
 	}
 
-	if (id == 0) {
-		iface = tracker_data_manager_get_writable_db_interface (data->manager);
+	iface = tracker_data_manager_get_writable_db_interface (data->manager);
 
-		id = tracker_data_update_get_new_service_id (data, &error);
+	id = tracker_data_update_get_new_service_id (data, &error);
 
-		if (id > 0) {
-			stmt = tracker_db_interface_create_statement (iface, TRACKER_DB_STATEMENT_CACHE_TYPE_UPDATE, &error,
-			                                              "INSERT INTO Resource (ID, Uri, BlankNode) VALUES (?, ?, ?)");
-		}
+	if (id > 0) {
+		stmt = tracker_db_interface_create_statement (iface, TRACKER_DB_STATEMENT_CACHE_TYPE_UPDATE, &error,
+							      "INSERT INTO Resource (ID, Uri, BlankNode) VALUES (?, ?, ?)");
+	}
 
-		if (stmt) {
-			tracker_db_statement_bind_int (stmt, 0, id);
-			tracker_db_statement_bind_text (stmt, 1, uri);
-			tracker_db_statement_bind_int (stmt, 2, g_str_has_prefix (uri, "urn:bnode:"));
-			tracker_db_statement_execute (stmt, &error);
-			g_object_unref (stmt);
-		}
+	if (stmt) {
+		tracker_db_statement_bind_int (stmt, 0, id);
+		tracker_db_statement_bind_text (stmt, 1, uri);
+		tracker_db_statement_bind_int (stmt, 2, g_str_has_prefix (uri, "urn:bnode:"));
+		tracker_db_statement_execute (stmt, &error);
+		g_object_unref (stmt);
+	}
 
-		if (error) {
-			g_error ("Could not ensure resource existence: %s", error->message);
-			g_error_free (error);
+	if (error) {
+		if (g_error_matches (error,
+		                     TRACKER_DB_INTERFACE_ERROR,
+		                     TRACKER_DB_CONSTRAINT)) {
+			id = query_resource_id (data, uri);
+
+			if (id != 0) {
+				if (create)
+					*create = FALSE;
+
+				g_hash_table_insert (data->update_buffer.resource_cache, g_strdup (uri), GINT_TO_POINTER (id));
+				g_error_free (error);
+				return id;
+			}
 		}
 
-		g_hash_table_insert (data->update_buffer.resource_cache, g_strdup (uri), GINT_TO_POINTER (id));
+		g_error ("Could not ensure resource existence: %s", error->message);
+		g_error_free (error);
 	}
 
+	if (create)
+		*create = TRUE;
+
+	id = tracker_db_interface_sqlite_get_last_insert_id (iface);
+	g_hash_table_insert (data->update_buffer.resource_cache, g_strdup (uri), GINT_TO_POINTER (id));
+
 	return id;
 }