- if table is not transactional, we don't create a transaction

- if table is temporary it's not crash-safe so we declare it
non-transactional (saves trnman calls, REDO/UNDO log writing,
and fixes the assertion failure at the first line of trnman_destroy()).


storage/maria/ha_maria.cc:
  if table is not transactional, no need to create a transaction:
  - it saves trnman calls (mutex locks etc)
  - it saves REDO and UNDO log writing
  - it closes a bug: if this is a temporary table, external_lock(F_RD|WRLCK)
  is not always paired with external_lock(F_UNLCK), which confuses the
  transaction logic in external_lock. As temp tables are not crash-safe
  and so not transactional in this Maria version, we skip transactions
  and de-confuse. Note that maria_lock_database(F_UNLCK) is
  properly called, so if the transaction logic moves from external_lock()
  to maria_lock_database() (probably TODO), transactional temp tables
  will be possible.
storage/maria/ma_create.c:
  temporary tables cannot be crash-safe as they are dropped at restart
storage/maria/maria_def.h:
  comment

3 files changed, 17 insertions, 11 deletions

diff --git a/storage/maria/ha_maria.cc b/storage/maria/ha_maria.cc
index c2f4d621305..f7fd417836a 100644
--- a/storage/maria/ha_maria.cc
+++ b/storage/maria/ha_maria.cc
@@ -1860,6 +1860,8 @@ int ha_maria::external_lock(THD *thd, int lock_type)
 {
   TRN *trn= THD_TRN;
   DBUG_ENTER("ha_maria::external_lock");
+  if (!file->s->base.transactional)
+    goto skip_transaction;
   if (!trn && lock_type != F_UNLCK) /* no transaction yet - open it now */
   {
     trn= trnman_new_trn(& thd->mysys_var->mutex,
@@ -1872,7 +1874,7 @@ int ha_maria::external_lock(THD *thd, int lock_type)
     DBUG_PRINT("info", ("THD_TRN set to 0x%lx", (ulong)trn));
     THD_TRN= trn;
     if (thd->options & (OPTION_NOT_AUTOCOMMIT | OPTION_BEGIN))
-      trans_register_ha(thd, true, maria_hton);
+      trans_register_ha(thd, TRUE, maria_hton);
   }
   if (lock_type != F_UNLCK)
   {
@@ -1905,6 +1907,7 @@ int ha_maria::external_lock(THD *thd, int lock_type)
       }
     }
   }
+skip_transaction:
   DBUG_RETURN(maria_lock_database(file, !table->s->tmp_table ?
                                   lock_type : ((lock_type == F_UNLCK) ?
                                                F_UNLCK : F_EXTRA_LCK)));
@@ -1913,11 +1916,11 @@ int ha_maria::external_lock(THD *thd, int lock_type)
 int ha_maria::start_stmt(THD *thd, thr_lock_type lock_type)
 {
   TRN *trn= THD_TRN;
-  DBUG_ASSERT(trn); // this may be called only after external_lock()
-  DBUG_ASSERT(lock_type != F_UNLCK);
-  if (!trnman_increment_locked_tables(trn))
+  if (file->s->base.transactional)
   {
-    trans_register_ha(thd, false, maria_hton);
+    DBUG_ASSERT(trn); // this may be called only after external_lock()
+    DBUG_ASSERT(lock_type != F_UNLCK);
+    /* As external_lock() was already called, don't increment locked_tables */
     trnman_new_statement(trn);
   }
   return 0;
diff --git a/storage/maria/ma_create.c b/storage/maria/ma_create.c
index 5dd6e0e1f93..d8660dd41cb 100644
--- a/storage/maria/ma_create.c
+++ b/storage/maria/ma_create.c
@@ -246,6 +246,14 @@ int maria_create(const char *name, enum data_file_type datafile_type,
       }
     }
   }
+
+  if (flags & HA_CREATE_TMP_TABLE)
+  {
+    options|= HA_OPTION_TMP_TABLE;
+    create_mode|= O_EXCL | O_NOFOLLOW;
+    /* temp tables are not crash-safe (dropped at restart) */
+    ci->transactional= FALSE;
+  }
   share.base.null_bytes= ci->null_bytes;
   share.base.original_null_bytes= ci->null_bytes;
   share.base.transactional= ci->transactional;
@@ -255,11 +263,6 @@ int maria_create(const char *name, enum data_file_type datafile_type,
   if (pack_reclength != INT_MAX32)
     pack_reclength+= max_field_lengths + long_varchar_count;
 
-  if (flags & HA_CREATE_TMP_TABLE)
-  {
-    options|= HA_OPTION_TMP_TABLE;
-    create_mode|= O_EXCL | O_NOFOLLOW;
-  }
   if (flags & HA_CREATE_CHECKSUM || (options & HA_OPTION_CHECKSUM))
   {
     options|= HA_OPTION_CHECKSUM;
diff --git a/storage/maria/maria_def.h b/storage/maria/maria_def.h
index 7a7261d0d6a..46ffac7cbc2 100644
--- a/storage/maria/maria_def.h
+++ b/storage/maria/maria_def.h
@@ -168,7 +168,7 @@ typedef struct st_ma_base_info
 
   /* The following are from the header */
   uint key_parts, all_key_parts;
-  /* If false, we disable logging, versioning etc */
+  /* If false, we disable logging, versioning, transaction etc */
   my_bool transactional;
 } MARIA_BASE_INFO;