Re: SELECT ... FOR UPDATE [WAIT integer | NOWAIT] for 8.5

Jeff Janes írta:
> On Thu, Sep 3, 2009 at 6:47 AM, Boszormenyi Zoltan <zb(at)cybertec(dot)at
> <mailto:zb(at)cybertec(dot)at>> wrote:
>
> Boszormenyi Zoltan írta:
> >
> > Okay, we implemented only the lock_timeout GUC.
> > Patch attached, hopefully in an acceptable form.
> > Documentation included in the patch, lock_timeout
> > works the same way as statement_timeout, takes
> > value in milliseconds and 0 disables the timeout.
> >
> > Best regards,
> > Zoltán Böszörményi
> >
>
> New patch attached. It's only regenerated for current CVS
> so it should apply cleanly.
>
>
> I'm getting segfaults, built in 32 bit linux with gcc
>
> bin/pg_ctl -D data start -l logfile -o "--lock_timeout=5"
>
> Session 1:
> jjanes=# begin;
> BEGIN
> jjanes=# select * from pgbench_branches where bid=3 for update;
> bid | bbalance | filler
> -----+----------+--------
> 3 | -3108950 |
> (1 row)
>
> Session 2:
> jjanes=# select * from pgbench_branches where bid=3 for update;
> ERROR: could not obtain lock on row in relation "pgbench_branches"
> jjanes=# select * from pgbench_branches where bid=3 for update;
> ERROR: could not obtain lock on row in relation "pgbench_branches"
> jjanes=# select * from pgbench_branches where bid=3 for update;
> ERROR: could not obtain lock on row in relation "pgbench_branches"
> jjanes=# set lock_timeout = 0 ;
> SET
> jjanes=# select * from pgbench_branches where bid=3 for update;
>
> <Session 2 is now blocked>
>
> Session1:
> jjanes=# commit;
> <long pause>
> server closed the connection unexpectedly
> This probably means the server terminated abnormally
> before or while processing the request.
> The connection to the server was lost. Attempting reset: Failed.
>
> I just realized I should have built with asserts turned on. I'll do
> that tomorrow, but don't want to delay this info until then, so I am
> sending it now.
>
> Cheers,
>
> Jeff

Thanks for the test. The same test worked perfectly at the time
I posted it and it also works perfectly on 8.4.1 *now*. So
something has changed between then and the current CVS,
because I was able to reproduce the segfault with the current
CVS HEAD. We'll have to update the patch obviously...

Best regards,
Zoltán Böszörményi

--
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----------------------------------
Zoltán Böszörményi
Cybertec Schönig & Schönig GmbH
http://www.postgresql.at/