BUG #15253: DROP/select/update query waiting for pg_dump

Hi,

On 2018-06-27 14:01:09 +0000, PG Bug reporting form wrote:

The following bug has been logged on the website:

Bug reference: 15253
Logged by: NIRBAN SEN
Email address: sennirban89@gmail.com
PostgreSQL version: Unsupported/Unknown
Operating system: rhel7
Description:

DROP/select/update queries are going into waiting state when pg_dump is
running.

DROP TABLE, and many other kinds of DDL, are indeed going to be blocked
by a concurrent pg_dump. That's expected and not a bug. SELECT / UPDATE
on their own won't.

Please note that the form you used is for reporting a bug, but I do not
see one in your report?

Greetings,

Andres Freund

On Wed, Jun 27, 2018 at 10:01 AM, PG Bug reporting form <
noreply@postgresql.org> wrote:

The following bug has been logged on the website:

Bug reference: 15253
Logged by: NIRBAN SEN
Email address: sennirban89@gmail.com
PostgreSQL version: Unsupported/Unknown
Operating system: rhel7
Description:

DROP/select/update queries are going into waiting state when pg_dump is
running.

I'm using 9.2.18 version.

That's not a bug. Selects and Updates alone should not block on a pg_dump,
but in conjunction with DROP they certainly can. You can't DROP a table
while it is being dumped, and you can't select from a table while it is
waiting to be dropped.

Cheers,

Jeff