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

MDEV-8989: ORDER BY optimizer ignores equality propagation

Browse Source 
Variant #4 of the fix.

Make ORDER BY optimization functions take into account multiple
equalities. This is done in several places:
- remove_const() checks whether we can sort the first table in the
  join, or we need to put rows into temp.table and then sort.
- test_if_order_by_key() checks whether there are indexes that
  can be used to produce the required ordering
- make_unireg_sortorder() constructs sort criteria for filesort.
This commit is contained in:
Sergei Petrunia
2016-05-23 21:15:01 +03:00
parent 9c9747fed3
commit 99cd5a962c
13 changed files with 414 additions and 21 deletions
Download Patch File Download Diff File Expand all files Collapse all files

2
sql/sql_table.cc
View File

@ -9472,7 +9472,7 @@ copy_data_between_tables(THD *thd, TABLE *from, TABLE *to,
if (thd->lex->select_lex.setup_ref_array(thd, order_num) ||
setup_order(thd, thd->lex->select_lex.ref_pointer_array,
&tables, fields, all_fields, order) ||
!(sortorder= make_unireg_sortorder(thd, order, &length, NULL)) ||
!(sortorder= make_unireg_sortorder(thd, NULL, 0, order, &length, NULL)) ||
(from->sort.found_records= filesort(thd, from, sortorder, length,
NULL, HA_POS_ERROR,
true,