Re: Possible stability issue: permanent hang on dropdb - Mailing list pgsql-bugs

From Robert Haas
Subject Re: Possible stability issue: permanent hang on dropdb
Date
Msg-id 603c8f071002061438t38f76186g8e06d4fa0fea494c@mail.gmail.com
Whole thread Raw
In response to Possible stability issue: permanent hang on dropdb  (The Fuzzy Chef <fuzzy@fuzzychef.org>)
Responses Re: Possible stability issue: permanent hang on dropdb  (Josh Berkus <josh@agliodbs.com>)
List pgsql-bugs
On Fri, Feb 5, 2010 at 9:50 PM, The Fuzzy Chef <fuzzy@fuzzychef.org> wrote:
> Just had a very odd thing happen with an 8.4.2 database, and am
> concerned it's an undiagnosed bug:
>
> (1) created and dropped the same database 10-15 times in the course of
> running some tests.
>
> (2) at one point, dropdb hung. =A0Indefinitely.
>
> (3) attempts to pg_cancel_backend on the DROP DATABASE process were
> futile. =A0yet no other queries were accessing that database according to
> pg_stat_activity.
>
> (4) pg_ctl -m fast did not shut down the server.
>
> (5) pg_ctl -m immediate did shut it down.
> (5a) realized pgbouncer was still running. =A0shut it down as well.
>
> (6) on restart, the server took several minutes to *start* recover mode.
> =A0then it got to a certain log segment, and hung indefinitely.
>
> (7) killed postgres
>
> (8) restarted again. =A0this time the server came up in about 20s, and is
> behaving normally. =A0The deleted database is not there.
>
> Setup:
> RHEL 5
> PostgreSQL 8.4.2, installed from yum.postgresql.org
> 8 databases and about 10G of data on the server
> pgbouncer running but NOT connected to the dropped database, just to two
> others
>
> I've made a full copy of my PGDATA directory if anyone wants me to test
> anything.

It's too bad you didn't capture a stack backtrace at step #3 or step
#6.  If you manage to reproduce the problem, that would be a good
thing to try to get.

...Robert

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