diff options
Diffstat (limited to 'sql/sql_base.cc')
| -rw-r--r-- | sql/sql_base.cc | 9 |
1 files changed, 9 insertions, 0 deletions
diff --git a/sql/sql_base.cc b/sql/sql_base.cc index 37d4c80a0d0..2614a7cd5be 100644 --- a/sql/sql_base.cc +++ b/sql/sql_base.cc @@ -368,6 +368,15 @@ bool close_cached_tables(THD *thd, bool if_wait_for_refresh, DESCRIPTION Marks all tables in the list which were used by current substatement (they are marked by its query_id) as free for reuse. + + NOTE + The reason we reset query_id is that it's not enough to just test + if table->query_id != thd->query_id to know if a table is in use. + + For example + SELECT f1_that_uses_t1() FROM t1; + In f1_that_uses_t1() we will see one instance of t1 where query_id is + set to query_id of original query. */ static void mark_used_tables_as_free_for_reuse(THD *thd, TABLE *table) |