Re: pg_restore encounter deadlock since PostgreSQL bringing up

On 11/16/2015 08:24 PM, zh1029 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?

To me this:

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

looks strange.

Can you look in the dump file and see where that is coming from?

>
> Brs.
>
>
>
> --
> View this message in context: http://postgresql.nabble.com/pg-restore-encounter-deadlock-since-PostgreSQL-bringing-up-tp5874146.html
> Sent from the PostgreSQL - general mailing list archive at Nabble.com.
>
>

--
Adrian Klaver
adrian(dot)klaver(at)aklaver(dot)com