database/mariadb
1
0
Fork 0
mirror of https://github.com/MariaDB/server.git synced 2025-08-01 03:47:19 +03:00
Code Activity

Fix for bug #31207: Test "join_nested" shows different strategy on IA64

Browse Source 
CPUs / Intel's ICC compile

The bug is a combination of two problems:

1. IA64/ICC MySQL binaries use glibc's qsort(), not the one in mysys.

2. The order relation implemented by join_tab_cmp() is not transitive,
i.e. it is possible to choose such a, b and c that (a < b) && (b < c)
but (c < a). This implies that result of a sort using the relation
implemented by join_tab_cmp() depends on the order in which
elements are compared, i.e. the result is implementation-specific. Since
choose_plan() uses qsort() to pre-sort the
join tables using join_tab_cmp() as a compare function, the results of
the sorting may vary depending on qsort() implementation.

It is neither possible nor important to implement a better ordering
algorithm in join_tab_cmp(). Therefore the only way to fix it is to
force our own qsort() to be used by renaming it to my_qsort(), so we don't depend
on linker to decide that.

This patch also "fixes" bug #20530: qsort redefinition violates the
standard.
This commit is contained in:
kaa@polly.(none)
2007-10-17 20:08:58 +04:00
parent 80a2d47b22
commit 6d1f3e8de5
21 changed files with 62 additions and 46 deletions
Download Patch File Download Diff File Expand all files Collapse all files

8
sql/opt_range.cc
View File

@ -3159,8 +3159,8 @@ TRP_ROR_INTERSECT *get_best_ror_intersect(const PARAM *param, SEL_TREE *tree,
ROR_SCAN_INFO's.
Step 2: Get best ROR-intersection using an approximate algorithm.
*/
qsort(tree->ror_scans, tree->n_ror_scans, sizeof(ROR_SCAN_INFO*),
(qsort_cmp)cmp_ror_scan_info);
my_qsort(tree->ror_scans, tree->n_ror_scans, sizeof(ROR_SCAN_INFO*),
(qsort_cmp)cmp_ror_scan_info);
DBUG_EXECUTE("info",print_ror_scans_arr(param->table, "ordered",
tree->ror_scans,
tree->ror_scans_end););
@ -3349,8 +3349,8 @@ TRP_ROR_INTERSECT *get_best_covering_ror_intersect(PARAM *param,
bitmap_get_first(&(*scan)->covered_fields);
}
qsort(ror_scan_mark, ror_scans_end-ror_scan_mark, sizeof(ROR_SCAN_INFO*),
(qsort_cmp)cmp_ror_scan_info_covering);
my_qsort(ror_scan_mark, ror_scans_end-ror_scan_mark, sizeof(ROR_SCAN_INFO*),
(qsort_cmp)cmp_ror_scan_info_covering);
DBUG_EXECUTE("info", print_ror_scans_arr(param->table,
"remaining scans",