Re: pg_restore encounter deadlock since PostgreSQL bringing up

On Tue, Nov 17, 2015 at 3:24 PM, zh1029 <zh1029(at)sina(dot)com> wrote:

> Hi,
>
> While start PostgreSQL(9.3.6) and execute pg_restore soon after PostgreSQL
> bringing up. I encounter pg_restore failure because of deadlock detected.
>
> postgres[2737]: [3-1] LOG: process 2737 detected deadlock while waiting
> for
> AccessExclusiveLock on relation 33337 of database 24577 after 1000.070 ms
> postgres[2737]: [3-2] STATEMENT: DROP SCHEMA public CASCADE;
> postgres[2737]: [4-1] err-1: deadlock detected
> postgres[2737]: [4-2] DETAIL: Process 2737 waits for AccessExclusiveLock
> on
> relation 33337 of database 24577; blocked by process 2720.
> postgres[2737]: [4-3] Process 2720 waits for AccessShareLock on
> relation 33344 of database 24577; blocked by process 2737.
> postgres[2737]: [4-4] Process 2737: DROP SCHEMA public CASCADE;
> postgres[2737]: [4-5] Process 2720: SELECT sequence_name,
> start_value, increment_by, CASE WHEN increment_by > 0 AND max_value =
> 9223372036854775807 THEN NULL WHEN increment_by < 0 AND max_value = -1
> THEN NULL ELSE max_value END AS max_value, CASE WHEN increment_by > 0
> AND min_value = 1 THEN NULL WHEN increment_by < 0 AND min_value =
> -9223372036854775807 THEN NULL ELSE min_value END AS min_value,
> cache_value, is_cycled FROM zonepreprovisioningrules_id_seq
> postgres[2737]: [4-6] HINT: See server log for query details.
> postgres[2737]: [4-7] STATEMENT: DROP SCHEMA public CASCADE;
>
> I suspect competition between process that bringing up PostgreSQL and
> process drop schema by pg_restore. So my question is how to guarantee (e.g
> by inquiring some parameters from system tables? ) PostgreSQL is totally
> start up to accept drop schema via pg_restore?
>

"pg_ctl -D <data-directory> status" command will let you know if the
PostgreSQL cluster is up and running.

Are you sure, you do not have any other processes running while pg_restore
process is running ? Whats the background of the process 2720 ?

Regards,
Venkata B N

Fujitsu Australia