MDEV-18794 Assertion `!m_innodb' failed in ha_partition::cmp_ref upon SELECT from partitioned table

System versioning assertion fix. Since DROP SYSTEM VERSIONING does not
change list of dropped keys we should handle a special case.

Caused by MDEV-19751. This fix deprecates MDEV-17091.

1 files changed, 21 insertions, 29 deletions

diff --git a/sql/sql_partition.cc b/sql/sql_partition.cc
index b7b400f490a..f7158a2b1ee 100644
--- a/sql/sql_partition.cc
+++ b/sql/sql_partition.cc
@@ -5986,26 +5986,35 @@ the generated partition syntax in a correct manner.
         }
       }
       /*
-        Prohibit inplace when partitioned by primary key and the primary key is dropped.
+        Prohibit inplace when partitioned by primary key and the primary key is changed.
       */
       if (!*partition_changed &&
           tab_part_info->part_field_array &&
           !tab_part_info->part_field_list.elements &&
           table->s->primary_key != MAX_KEY)
       {
-        KEY *primary_key= table->key_info + table->s->primary_key;
-        List_iterator_fast<Alter_drop> drop_it(alter_info->drop_list);
-        const char *primary_name= primary_key->name.str;
-        const Alter_drop *drop;
-        drop_it.rewind();
-        while ((drop= drop_it++))
+
+        if (alter_info->flags & (ALTER_DROP_SYSTEM_VERSIONING |
+                                 ALTER_ADD_SYSTEM_VERSIONING))
         {
-          if (drop->type == Alter_drop::KEY &&
-              0 == my_strcasecmp(system_charset_info, primary_name, drop->name))
-            break;
+          *partition_changed= true;
+        }
+        else
+        {
+          KEY *primary_key= table->key_info + table->s->primary_key;
+          List_iterator_fast<Alter_drop> drop_it(alter_info->drop_list);
+          const char *primary_name= primary_key->name.str;
+          const Alter_drop *drop;
+          drop_it.rewind();
+          while ((drop= drop_it++))
+          {
+            if (drop->type == Alter_drop::KEY &&
+                0 == my_strcasecmp(system_charset_info, primary_name, drop->name))
+              break;
+          }
+          if (drop)
+            *partition_changed= TRUE;
         }
-        if (drop)
-          *partition_changed= TRUE;
       }
     }
     if (thd->work_part_info)
@@ -6039,23 +6048,6 @@ the generated partition syntax in a correct manner.
         }
       }
 
-      // In case of PARTITION BY KEY(), check if primary key has changed
-      // System versioning also implicitly adds/removes primary key parts
-      if (alter_info->partition_flags == 0 && part_info->list_of_part_fields
-          && part_info->part_field_list.elements == 0)
-      {
-        if (alter_info->flags & (ALTER_DROP_SYSTEM_VERSIONING |
-                                 ALTER_ADD_SYSTEM_VERSIONING))
-          *partition_changed= true;
-
-        List_iterator<Key> it(alter_info->key_list);
-        Key *key;
-        while((key= it++) && !*partition_changed)
-        {
-          if (key->type == Key::PRIMARY)
-            *partition_changed= true;
-        }
-      }
       /*
         Set up partition default_engine_type either from the create_info
         or from the previus table