Clean-up, give better names, add comments to

thd->in_multi_stmt_transaction() and thd->active_transaction().


include/mysql_com.h:
  Comment SERVER_STATUS_IN_TRANS flag.
sql/ha_ndbcluster.cc:
  Rename: thd->in_multi_stmt_transaction() -> 
  thd->in_multi_stmt_transaction_mode().
sql/handler.cc:
  Add comments.
sql/log.cc:
  Rename: thd->in_multi_stmt_transaction() -> 
  thd->in_multi_stmt_transaction_mode().
sql/log_event.cc:
  Rename: thd->in_multi_stmt_transaction() -> 
  thd->in_multi_stmt_transaction_mode().
sql/sql_base.cc:
  Rename: thd->in_multi_stmt_transaction() -> 
  thd->in_multi_stmt_transaction_mode().
sql/sql_cache.cc:
  Rename: thd->active_transaction() ->
  thd->in_active_multi_stmt_transaction().
sql/sql_class.cc:
  Rename: thd->in_multi_stmt_transaction() -> 
  thd->in_multi_stmt_transaction_mode().
sql/sql_class.h:
  Rename and comment two transaction processing- related methods.
sql/sql_parse.cc:
  Rename: thd->in_multi_stmt_transaction() -> 
  thd->in_multi_stmt_transaction_mode().
  Rename: thd->active_transaction() ->
  thd->in_active_multi_stmt_transaction().
sql/sql_prepare.cc:
  Rename: thd->in_multi_stmt_transaction() -> 
  thd->in_multi_stmt_transaction_mode().
sql/sql_rename.cc:
  Rename: thd->active_transaction() ->
  thd->in_active_multi_stmt_transaction().
sql/sql_table.cc:
  Rename: thd->active_transaction() ->
  thd->in_active_multi_stmt_transaction().
sql/sys_vars.cc:
  Rename: thd->active_transaction() ->
  thd->in_active_multi_stmt_transaction().
sql/transaction.cc:
  Rename: thd->in_multi_stmt_transaction() -> 
  thd->in_multi_stmt_transaction_mode().
  Rename: thd->active_transaction() ->
  thd->in_active_multi_stmt_transaction().

1 files changed, 22 insertions, 3 deletions

diff --git a/sql/handler.cc b/sql/handler.cc
index ee02441e7ff..c0a5e2ff55c 100644
--- a/sql/handler.cc
+++ b/sql/handler.cc
@@ -1245,7 +1245,14 @@ end:
 /**
   @note
   This function does not care about global read lock. A caller should.
+
+  @param[in]  all  Is set in case of explicit commit
+                   (COMMIT statement), or implicit commit
+                   issued by DDL. Is not set when called
+                   at the end of statement, even if
+                   autocommit=1.
 */
+
 int ha_commit_one_phase(THD *thd, bool all)
 {
   int error=0;
@@ -1253,9 +1260,15 @@ int ha_commit_one_phase(THD *thd, bool all)
   /*
     "real" is a nick name for a transaction for which a commit will
     make persistent changes. E.g. a 'stmt' transaction inside a 'all'
-    transation is not 'real': even though it's possible to commit it,
+    transaction is not 'real': even though it's possible to commit it,
     the changes are not durable as they might be rolled back if the
     enclosing 'all' transaction is rolled back.
+    We establish the value of 'is_real_trans' by checking
+    if it's an explicit COMMIT/BEGIN statement, or implicit
+    commit issued by DDL (all == TRUE), or if we're running
+    in autocommit mode (it's only in the autocommit mode
+    ha_commit_one_phase() can be called with an empty
+    transaction.all.ha_list, see why in trans_register_ha()).
   */
   bool is_real_trans=all || thd->transaction.all.ha_list == 0;
   Ha_trx_info *ha_info= trans->ha_list, *ha_info_next;
@@ -1303,9 +1316,15 @@ int ha_rollback_trans(THD *thd, bool all)
   /*
     "real" is a nick name for a transaction for which a commit will
     make persistent changes. E.g. a 'stmt' transaction inside a 'all'
-    transation is not 'real': even though it's possible to commit it,
+    transaction is not 'real': even though it's possible to commit it,
     the changes are not durable as they might be rolled back if the
     enclosing 'all' transaction is rolled back.
+    We establish the value of 'is_real_trans' by checking
+    if it's an explicit COMMIT or BEGIN statement, or implicit
+    commit issued by DDL (in these cases all == TRUE),
+    or if we're running in autocommit mode (it's only in the autocommit mode
+    ha_commit_one_phase() is called with an empty
+    transaction.all.ha_list, see why in trans_register_ha()).
   */
   bool is_real_trans=all || thd->transaction.all.ha_list == 0;
   DBUG_ENTER("ha_rollback_trans");
@@ -1358,7 +1377,7 @@ int ha_rollback_trans(THD *thd, bool all)
     if (all)
       thd->variables.tx_isolation=thd->session_tx_isolation;
   }
-  /* Always cleanup. Even if there nht==0. There may be savepoints. */
+  /* Always cleanup. Even if nht==0. There may be savepoints. */
   if (is_real_trans)
     thd->transaction.cleanup();
   if (all)