Bug #37492 timing bug in subselect.test
Submitted: 18 Jun 2008 21:07 Modified: 10 Jul 2008 21:48
Reporter: Timothy Smith
Status: Closed
Category:Server: Tests Severity:S3 (Non-critical)
Version:5.0, 5.1, 6.0 OS:Any
Assigned to: Matthias Leich Target Version:5.0+
Tags: pbfail
Triage: D3 (Medium)

[18 Jun 2008 21:07] Timothy Smith 
Description:
A very rare timing bug in subselect.test due to --sleep 1 and REPLACE DELAYED
interaction.

main.subselect_no_opts         [ fail ]

---
C:/cygwin/home/pushbuild/pb1/pb/mysql-6.0-build/187/mysql-6.0.6-alpha-pb187/mysql-test/r/subselect_no_opts.result	2008-05-29
08:11:23.000000000 +0300
+++
C:\cygwin\home\pushbuild\pb1\pb\mysql-6.0-build\187\mysql-6.0.6-alpha-pb187\mysql-test\r\subselect_no_opts.reject	2008-05-29
09:46:30.905625000 +0300
@@ -706,7 +706,7 @@
 select * from t1;
 x	y
 1	3
-4	2
+4	1
 replace LOW_PRIORITY into t1 (x, y) VALUES ((SELECT a+1 FROM t2), (SELECT a FROM t2));
 select * from t1;
 x	y

mysqltest: Result content mismatch

Looking at the test case, it appears simple:

replace DELAYED into t1 (x, y) VALUES ((SELECT a+3 FROM t2), (SELECT a+1 FROM t2));
-- sleep 1
select * from t1;

The --sleep 1 looks to be insufficient.

How to repeat:
This is the only example I find in PushBuild:

https://intranet.mysql.com/secure/pushbuild/xref.pl?startdate=&enddate=&dir=&plat=&testtyp...

Suggested fix:
Perhaps ignore this as too infrequent to care about.  Perhaps increase sleep time (not
ideal, but easy).  Perhaps find some way to inspect the delayed insert queue (sounds too
difficult).
[20 Jun 2008 18:44] Matthias Leich 
I had a short look into the 5.0 version of this test
and it looks like that
- there are several places with the too optimistic
  assumption that the modifications made by a statement
  with DELAYED must be visible after a sleep time of
  1 second
  IMHO all should be fixed. It's just a question of time
  when the next weak subtest will fail on an overloaded box.
- most probably a wait routine checking if all expected
  changes are in place could be used.
- the test needs also some basic maintenance (replace
  error numbers by error names)
[20 Jun 2008 22:55] Matthias Leich 
Minor weakness found during stability testing and also
to be fixed:
./mysql-test-run.pl `perl -e 'for (1 .. 20) { print "subselect "}'`
Logging: ./mysql-test-run.pl subselect subselect .....
.....
TEST                           RESULT         TIME (ms)
-------------------------------------------------------

subselect                      [ pass ]          19531
subselect                      [ fail ]

mysqltest: At line 1039: query 'select a, (select max(b) 
from t1) into outfile "subselect.out.file.1" from t1' failed:
 1086: File 'subselect.out.file.1' already exists

= The test does not remove this file after testing
[23 Jun 2008 16:11] Bugs System 
A patch for this bug has been committed. After review, it may
be pushed to the relevant source trees for release in the next
version. You can access the patch from:

  http://lists.mysql.com/commits/48336
[24 Jun 2008 12:52] Bugs System 
A patch for this bug has been committed. After review, it may
be pushed to the relevant source trees for release in the next
version. You can access the patch from:

  http://lists.mysql.com/commits/48382
[24 Jun 2008 13:35] Bugs System 
A patch for this bug has been committed. After review, it may
be pushed to the relevant source trees for release in the next
version. You can access the patch from:

  http://lists.mysql.com/commits/48385
[24 Jun 2008 19:57] Bugs System 
A patch for this bug has been committed. After review, it may
be pushed to the relevant source trees for release in the next
version. You can access the patch from:

  http://lists.mysql.com/commits/48418
[25 Jun 2008 17:00] Bugs System 
A patch for this bug has been committed. After review, it may
be pushed to the relevant source trees for release in the next
version. You can access the patch from:

  http://lists.mysql.com/commits/48500
[25 Jun 2008 19:02] Bugs System 
A patch for this bug has been committed. After review, it may
be pushed to the relevant source trees for release in the next
version. You can access the patch from:

  http://lists.mysql.com/commits/48507
[25 Jun 2008 19:25] Bugs System 
A patch for this bug has been committed. After review, it may
be pushed to the relevant source trees for release in the next
version. You can access the patch from:

  http://lists.mysql.com/commits/48509
[25 Jun 2008 19:31] Bugs System 
A patch for this bug has been committed. After review, it may
be pushed to the relevant source trees for release in the next
version. You can access the patch from:

  http://lists.mysql.com/commits/48510
[25 Jun 2008 19:32] Bugs System 
A patch for this bug has been committed. After review, it may
be pushed to the relevant source trees for release in the next
version. You can access the patch from:

  http://lists.mysql.com/commits/48511
[25 Jun 2008 19:33] Bugs System 
A patch for this bug has been committed. After review, it may
be pushed to the relevant source trees for release in the next
version. You can access the patch from:

  http://lists.mysql.com/commits/48512
[25 Jun 2008 19:38] Matthias Leich 
Pushed to
mysql-5.0-bugteam
mysql-5.1-bugteam
mysql-6.0-bugteam
The fix removes weaknesses within the tests. There is
no documentation needed.
[26 Jun 2008 15:17] Bugs System 
Pushed into 5.0.66
[26 Jun 2008 15:19] Bugs System 
Pushed into 5.0.66
[26 Jun 2008 15:32] Bugs System 
Pushed into 5.0.66
[26 Jun 2008 15:40] Bugs System 
Pushed into 5.0.66
[27 Jun 2008 18:21] Bugs System 
Pushed into 5.0.66
[10 Jul 2008 21:48] Paul DuBois 
No changelog entry needed.
[28 Jul 2008 15:47] Bugs System 
Pushed into 5.0.68  (revid:kpettersson@mysql.com-20080715152926-s5kgnqhtu93b3c8v) (pib:2)
(Retry automatic marking, to ensure nothing is missed. cm01)
[28 Jul 2008 18:50] Bugs System 
Pushed into 5.1.27  (revid:joerg@mysql.com-20080626161101-h5hsaluwtf05xdr2) (version
source revid:joerg@mysql.com-20080626161101-h5hsaluwtf05xdr2) (pib:3)