MDEV 15532 Assertion `!log->same_pk' failed in row_log_table_apply_delete

The reason for the failure is that
thd->mdl_context.release_transactional_locks()
was called after commit & rollback even in cases where the current
transaction is still active.

For 10.2, 10.3 and 10.4 the fix is simple:
- Replace all calls to thd->mdl_context.release_transactional_locks() with
  thd->release_transactional_locks(). The thd function will only call
  the mdl_context function if there are no active transactional locks.
  In 10.6 we will better fix where we will change the return value for
  some trans_xxx() functions to indicate if transaction did close the
  transaction or not. This will avoid the need of the indirect call.

Other things:
- trans_xa_commit() and trans_xa_rollback() will automatically
  call release_transactional_locks() if the transaction is closed.
- We can't do that for the other functions as the caller of many of these
  are doing additional work (like close_thread_tables) before calling
  release_transactional_locks().
- Added missing abort_result_set() and missing DBUG_RETURN in
  select_create::send_eof()
- Fixed wrong indentation in injector::transaction::commit()

1 files changed, 14 insertions, 16 deletions

diff --git a/sql/sql_parse.cc b/sql/sql_parse.cc
index 83100e743ad..0166c4554e7 100644
--- a/sql/sql_parse.cc
+++ b/sql/sql_parse.cc
@@ -2034,7 +2034,7 @@ bool dispatch_command(enum enum_server_command command, THD *thd,
         locks.
       */
       trans_rollback_implicit(thd);
-      thd->mdl_context.release_transactional_locks();
+      thd->release_transactional_locks();
     }
 
     thd->cleanup_after_query();
@@ -2099,7 +2099,7 @@ bool dispatch_command(enum enum_server_command command, THD *thd,
     ulonglong options= (ulonglong) (uchar) packet[0];
     if (trans_commit_implicit(thd))
       break;
-    thd->mdl_context.release_transactional_locks();
+    thd->release_transactional_locks();
     if (check_global_access(thd,RELOAD_ACL))
       break;
     general_log_print(thd, command, NullS);
@@ -2132,7 +2132,7 @@ bool dispatch_command(enum enum_server_command command, THD *thd,
     if (trans_commit_implicit(thd))
       break;
     close_thread_tables(thd);
-    thd->mdl_context.release_transactional_locks();
+    thd->release_transactional_locks();
     my_ok(thd);
     break;
   }
@@ -2934,7 +2934,7 @@ err:
   /* Close tables and release metadata locks. */
   close_thread_tables(thd);
   DBUG_ASSERT(!thd->locked_tables_mode);
-  thd->mdl_context.release_transactional_locks();
+  thd->release_transactional_locks();
   return TRUE;
 }
 
@@ -3406,7 +3406,7 @@ mysql_execute_command(THD *thd)
       /* Commit the normal transaction if one is active. */
       bool commit_failed= trans_commit_implicit(thd);
       /* Release metadata locks acquired in this transaction. */
-      thd->mdl_context.release_transactional_locks();
+      thd->release_transactional_locks();
       if (commit_failed)
       {
         WSREP_DEBUG("implicit commit failed, MDL released: %lld",
@@ -4645,7 +4645,7 @@ mysql_execute_command(THD *thd)
     {
       res= trans_commit_implicit(thd);
       thd->locked_tables_list.unlock_locked_tables(thd);
-      thd->mdl_context.release_transactional_locks();
+      thd->release_transactional_locks();
       thd->variables.option_bits&= ~(OPTION_TABLE_LOCK);
     }
     if (thd->global_read_lock.is_acquired())
@@ -4659,7 +4659,7 @@ mysql_execute_command(THD *thd)
     res= trans_commit_implicit(thd);
     thd->locked_tables_list.unlock_locked_tables(thd);
     /* Release transactional metadata locks. */
-    thd->mdl_context.release_transactional_locks();
+    thd->release_transactional_locks();
     if (res)
       goto error;
 
@@ -5313,7 +5313,7 @@ mysql_execute_command(THD *thd)
     DBUG_PRINT("info", ("Executing SQLCOM_BEGIN  thd: %p", thd));
     if (trans_begin(thd, lex->start_transaction_opt))
     {
-      thd->mdl_context.release_transactional_locks();
+      thd->release_transactional_locks();
       WSREP_DEBUG("BEGIN failed, MDL released: %lld",
                   (longlong) thd->thread_id);
       goto error;
@@ -5331,7 +5331,7 @@ mysql_execute_command(THD *thd)
                       (thd->variables.completion_type == 2 &&
                        lex->tx_release != TVL_NO));
     bool commit_failed= trans_commit(thd);
-    thd->mdl_context.release_transactional_locks();
+    thd->release_transactional_locks();
     if (commit_failed)
     {
       WSREP_DEBUG("COMMIT failed, MDL released: %lld",
@@ -5382,7 +5382,7 @@ mysql_execute_command(THD *thd)
                       (thd->variables.completion_type == 2 &&
                        lex->tx_release != TVL_NO));
     bool rollback_failed= trans_rollback(thd);
-    thd->mdl_context.release_transactional_locks();
+    thd->release_transactional_locks();
 
     if (rollback_failed)
     {
@@ -5859,7 +5859,6 @@ mysql_execute_command(THD *thd)
   case SQLCOM_XA_COMMIT:
   {
     bool commit_failed= trans_xa_commit(thd);
-    thd->mdl_context.release_transactional_locks();
     if (commit_failed)
     {
       WSREP_DEBUG("XA commit failed, MDL released: %lld",
@@ -5877,7 +5876,6 @@ mysql_execute_command(THD *thd)
   case SQLCOM_XA_ROLLBACK:
   {
     bool rollback_failed= trans_xa_rollback(thd);
-    thd->mdl_context.release_transactional_locks();
     if (rollback_failed)
     {
       WSREP_DEBUG("XA rollback failed, MDL released: %lld",
@@ -6095,7 +6093,7 @@ finish:
       all storage engines including binary log.
     */
     trans_rollback_implicit(thd);
-    thd->mdl_context.release_transactional_locks();
+    thd->release_transactional_locks();
   }
   else if (stmt_causes_implicit_commit(thd, CF_IMPLICIT_COMMIT_END))
   {
@@ -6108,7 +6106,7 @@ finish:
       /* Commit the normal transaction if one is active. */
       trans_commit_implicit(thd);
       thd->get_stmt_da()->set_overwrite_status(false);
-      thd->mdl_context.release_transactional_locks();
+      thd->release_transactional_locks();
     }
   }
   else if (! thd->in_sub_stmt && ! thd->in_multi_stmt_transaction_mode())
@@ -6123,7 +6121,7 @@ finish:
       - If in autocommit mode, or outside a transactional context,
       automatically release metadata locks of the current statement.
     */
-    thd->mdl_context.release_transactional_locks();
+    thd->release_transactional_locks();
   }
   else if (! thd->in_sub_stmt)
   {
@@ -6145,7 +6143,7 @@ finish:
   {
     WSREP_DEBUG("Forcing release of transactional locks for thd: %lld",
                 (longlong) thd->thread_id);
-    thd->mdl_context.release_transactional_locks();
+    thd->release_transactional_locks();
   }
 #endif /* WITH_WSREP */