MySQL Bugs: #44511: MTR2: add an option not to kill other servers when one from the group exits

Bug #44511	MTR2: add an option not to kill other servers when one from the group exits
Submitted:	28 Apr 2009 11:21	Modified:	29 May 2009 1:14
Reporter:	Elena Stepanova	Email Updates:
Status:	Closed	Impact on me:	None
Category:	Tools: MTR / mysql-test-run	Severity:	S4 (Feature request)
Version:		OS:	Any
Assigned to:	Bjørn Munch	CPU Architecture:	Any

Description:
When MTR2 is launched with --start or --start-dirty option to run *more than one* server, e.g. master and slave, it keeps watching all started servers; as soon as at least one of them exits (on whatever reason, even if it was shut down properly), MTR2 kills all other servers immediately and aborts.

It brings some problems in our test routine. For example, in some scenarios we have to keep extra servers running idle just so those we are interested in don't get killed; or, if something happens, e.g. master crashes, we would sometimes prefer to keep slave running for investigation purposes, or at least shut down gracefully, but not killed; etc.

What we need is a way to start a group of servers via MTR, but without the described kind of dependency.

How to repeat:
perl ./mysql-test-run.pl --start rpl_alter

# shut down one of the two started servers, e.g. slave
=> master dies

Suggested fix:
Description:

Current behavior:
- If MTR2 is launched with --start or --start-dirty, after starting servers it calls subroutine 'wait_any' from SafeProcess.pm, and waits for it to return.
- The subroutine monitors all started processes and returns an error as soon as at least one of monitored processes exits.

Suggested change:
- If MTR2 is launched with --start or --start-dirty option *and a new option --wait-all*, instead of calling 'wait_any' subroutine it will call the new one 'wait_all';
- in all other cases the behavior will be the same as now;
- the new subroutine in SafeProcess.pm will look very similar to wait_any, but will return only when *all* monitored processes exit.

Thus, we encapsulate all changes in SafeProcess.pm in the new function, and in mysql-test-run.pl -- under the new option.

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/72904

2785 Bjorn Munch	2009-04-28
      Bug #44511 MTR2: add an option not to kill other servers when one from the group exits
      MTR would die as soon as one server terminates
      Implemented --wait-all option and associated subroutine
      modified:
        mysql-test/lib/My/SafeProcess.pm
        mysql-test/mysql-test-run.pl

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/73030

2786 Bjorn Munch	2009-04-29
       Bug #44511 MTR2: add an option not to kill other servers when one from the group exits
      MTR would die as soon as one server terminates
      Implemented --wait-all option and associated subroutine
      modified:
        mysql-test/lib/My/SafeProcess.pm
        mysql-test/mysql-test-run.pl

You might want to check if 'wait_any' returns a process and print a message if it doesn't. Or is it enough with the code already at the end of 'wait_any'?

Pushed to 6.0-mtr and 5.1-mtr

Response to last comment: code at end of wait_any should be enough

Pushed into 6.0.12-alpha (revid:alik@sun.com-20090514161729-xiup7q8jlu1zfy7s) (version source revid:bjorn.munch@sun.com-20090429184140-noy2sqeo0gwtji4g) (merge vers: 6.0.12-alpha) (pib:6)

Test suite changes. No changelog entry needed.

Setting report to NDI pending push into 5.1.x.

Pushed into 5.1.36 (revid:joro@sun.com-20090528073639-yohsb4q1jzg7ycws) (version source revid:bjorn.munch@sun.com-20090525205831-zitq9aysxy5zgf5r) (merge vers: 5.1.36) (pib:6)

Test suite change. No changelog entry needed.

Pushed into 5.1.37-ndb-7.0.8 (revid:jonas@mysql.com-20090826132541-yablppc59e3yb54l) (version source revid:jonas@mysql.com-20090826132541-yablppc59e3yb54l) (merge vers: 5.1.37-ndb-7.0.8) (pib:11)

Pushed into 5.1.37-ndb-6.3.27 (revid:jonas@mysql.com-20090826105955-bkj027t47gfbamnc) (version source revid:jonas@mysql.com-20090826105955-bkj027t47gfbamnc) (merge vers: 5.1.37-ndb-6.3.27) (pib:11)

Pushed into 5.1.37-ndb-6.2.19 (revid:jonas@mysql.com-20090825194404-37rtosk049t9koc4) (version source revid:jonas@mysql.com-20090825194404-37rtosk049t9koc4) (merge vers: 5.1.37-ndb-6.2.19) (pib:11)

Pushed into 5.1.35-ndb-7.1.0 (revid:magnus.blaudd@sun.com-20090827163030-6o3kk6r2oua159hr) (version source revid:jonas@mysql.com-20090826132541-yablppc59e3yb54l) (merge vers: 5.1.37-ndb-7.0.8) (pib:11)