database/mariadb
1
0
Fork 0
mirror of https://github.com/MariaDB/server.git synced 2025-07-30 16:24:05 +03:00
Code Activity

BUG#834739: Wrong result with 3-way inner join, LooseScan,multipart keys

Browse Source 
- Don't use join buffering for tables that are within ranges that are 
  covered by LooseScan strategy.
This commit is contained in:
Sergey Petrunya
2011-09-05 20:51:37 +04:00
parent 6035d0d755
commit e1435a5178
6 changed files with 120 additions and 3 deletions
Download Patch File Download Diff File Expand all files Collapse all files

10
sql/sql_select.cc
View File

@ -7100,6 +7100,7 @@ get_best_combination(JOIN *join)
goto loop_end; // Handled in make_join_stat..
j->loosescan_match_tab= NULL; //non-nulls will be set later
j->inside_loosescan_range= FALSE;
j->ref.key = -1;
j->ref.key_parts=0;
@ -8984,6 +8985,15 @@ uint check_join_cache_usage(JOIN_TAB *tab,
if (tab->use_quick == 2)
goto no_join_cache;
/*
Don't use join cache if we're inside a join tab range covered by LooseScan
strategy (TODO: LooseScan is very similar to FirstMatch so theoretically it
should be possible to use join buffering in the same way we're using it for
multi-table firstmatch ranges).
*/
if (tab->inside_loosescan_range)
goto no_join_cache;
if (tab->is_inner_table_of_semi_join_with_first_match() &&
!join->allowed_semijoin_with_cache)