Bug #7266 Test failure: 'greedy_optimizer'
Submitted: 14 Dec 2004 13:45 Modified: 16 Dec 2004 16:25
Reporter: Joerg Bruehe Email Updates:
Status: Closed Impact on me:
None 
Category:MySQL Server Severity:S1 (Critical)
Version:5.0.3-pre OS:Linux (Linux/Athlon)
Assigned to: Timour Katchaounov CPU Architecture:Any

[14 Dec 2004 13:45] Joerg Bruehe
Description:
Test 'greedy_optimizer' fails for me in current 5.0,
both with and without the option '--ps-protocol'.

This is a non-debug build: 'compile-pentium-max'.

Failure report:
-------------------------------------------------------
*** r/greedy_optimizer.result   2004-11-05 12:13:03.000000000 +0300
--- r/greedy_optimizer.reject   2004-12-14 12:22:04.000000000 +0300
***************
*** 122,132 ****
  id    select_type     table   type    possible_keys   key     key_len ref     rows    Extra
  1     SIMPLE  t1      ALL     NULL    NULL    NULL    NULL    3
  1     SIMPLE  t2      ALL     NULL    NULL    NULL    NULL    6       Using where
! 1     SIMPLE  t3      eq_ref  PRIMARY PRIMARY 4       test.t2.c22     1
! 1     SIMPLE  t4      ALL     NULL    NULL    NULL    NULL    12      Using where
! 1     SIMPLE  t5      eq_ref  PRIMARY PRIMARY 4       test.t4.c42     1
! 1     SIMPLE  t6      ALL     NULL    NULL    NULL    NULL    18      Using where
  1     SIMPLE  t7      eq_ref  PRIMARY PRIMARY 4       test.t6.c62     1       Using index
  show status like 'Last_query_cost';
  Variable_name Value
  Last_query_cost       821.838037
--- 122,132 ----
  id    select_type     table   type    possible_keys   key     key_len ref     rows    Extra
  1     SIMPLE  t1      ALL     NULL    NULL    NULL    NULL    3
  1     SIMPLE  t2      ALL     NULL    NULL    NULL    NULL    6       Using where
! 1     SIMPLE  t6      ALL     NULL    NULL    NULL    NULL    18
  1     SIMPLE  t7      eq_ref  PRIMARY PRIMARY 4       test.t6.c62     1       Using index
+ 1     SIMPLE  t4      ALL     NULL    NULL    NULL    NULL    12
+ 1     SIMPLE  t3      eq_ref  PRIMARY PRIMARY 4       test.t2.c22     1       Using where
+ 1     SIMPLE  t5      eq_ref  PRIMARY PRIMARY 4       test.t4.c42     1       Using where
  show status like 'Last_query_cost';
  Variable_name Value
  Last_query_cost       821.838037
***************
*** 134,192 ****
...
Similar re-orderings and adding/dropping 'Using where' continue throughout that range of line numbers.
...
-------------------------------------------------------

Latest changeset on my PC:
ChangeSet@1.1738, 2004-12-14 13:41:32+03:00, gluh@gluh.mysql.r18.ru
  Fix for bug #7223: information_schema: error in "views"

The error is older, as I got it already yesterday but did not yet report.

How to repeat:
Run the test suite.
[16 Dec 2004 16:25] Timour Katchaounov
The bug was due to that there was a 0.001 factor added to the cost in the new
greedy optimizer, but it was not added to the old optimizer.