Re: Error on vacuum: xmin before relfrozenxid

Hi,

On 2018-05-22 16:18:20 +0200, Paolo Crosato wrote:
> PostgreSQL version number you are running:
>
> PostgreSQL 10.4 on x86_64-pc-linux-gnu, compiled by gcc (GCC) 4.8.5
> 20150623 (Red Hat 4.8.5-28), 64-bit
>
> How you installed PostgreSQL:
>
> From the pgdg yum repositories.
>
> Changes made to the settings in the postgresql.conf file:  see Server
> Configuration for a quick way to list them all.
> May 20 16:06:04 ubipgsql01 postgres[26739]: [1380-1] user=,db=,client=
> ERROR:  found xmin 2889675859 from before relfrozenxid 400011439
> May 20 16:06:04 ubipgsql01 postgres[26739]: [1380-2] user=,db=,client=
> CONTEXT:  automatic vacuum of table "postgres.pg_catalog.pg_authid"
>

> postgres=# select xmin from pg_authid ;
>     xmin
> ------------
>           1
>           1
>           1
>           1
>           1
>         557
>     7216348
>   110077819
>   110511334
>  3031994631
>  3032044199
>  3032044199
>  3032044199
>  3032070282
> (14 rows)
>
> postgres=# select relfrozenxid from pg_class where relname='pg_authid';
>  relfrozenxid
> --------------
>     400011439
> (1 row)
>
> postgres=#
>
> Is this a sympthom of data corruption or transaction wraparound due to the
> long running transaction that we killed weeks ago?

That shouldn't be the sole cause.


> This is the only table in the whole cluster that has this error. We
> are monitoring transactions wraparound with the the check_postgres.pl
> script, the check is still running fine and no alert was given at all
> since the cluster has been running.
>
> Thank you in advance for any answer.

Could you report the result of
select ctid, xmin, xmax from pg_authid ;

and
CREATE EXTENSION pageinspect;
SELECT * FROM heap_page_items(get_raw_page('pg_authid', 0));

Thanks.
Greetings,

Andres Freund