Re:

Sorry, dear mailing list, somehow my email got sent before I finished it :-(

I will go on and repeat. Please bear with me!

I am currently worried about an error that shows up in our log files since
a few weeks:

2013-11-15 07:13:13 UTC [22668]: [2-1] ERROR: MultiXactId 2683601542 does
no longer exist -- apparent wraparound
2013-11-15 07:13:13 UTC [22668]: [3-1] CONTEXT: automatic vacuum of table
"scoreloop.public.gamer_device_sightings"

It is always the same MultiXactId.
It seems that "autovacuum" is active on that table, but it seems to have
restarted today in the morning:

select query_start, query, state, pid from pg_stat_activity where query
LIKE 'autovacuum%' ;

# select query_start, query, state, pid from pg_stat_activity where query
LIKE 'autovacuum%' ;

query_start | query
| state | pid
-------------------------------+----------------------------------------------------------------------------------+--------+------
2013-11-15 07:13:13.281202+00 | autovacuum: VACUUM ANALYZE
public.gamer_device_sightings (to prevent wraparound) | active | 4360

There are a few locks on tat table:

# select c.oid,c.relname,l.pid,l.mode,l.granted from pg_class c join
pg_locks l on c.oid=l.relation where l.pid='4360' order by l.pid;
oid | relname | pid | mode
| granted
-------+------------------------------------------+------+--------------------------+---------
19862 | index_gamer_device_sightings_on_gamer_id | 4360 | RowExclusiveLock
| t
19719 | gamer_device_sightings_pkey | 4360 |
RowExclusiveLock | t
19309 | gamer_device_sightings | 4360 |
ShareUpdateExclusiveLock | t

The error I described seems to terminate the auto vacuum process: It has
never finished on that table.
It is the only table without a finished vacuum. So I guess the above error
is the reason for this.

Is there anything that I can do to get that fixed? Should I worry about the
error? (I would not if the vacuum would run through).

Any tips, any help would be much appreciated!

Thank you very much! And sorry once more for my posting mistake
Karl

On Fri, Nov 15, 2013 at 10:16 AM, Karl Hafner <karl(at)scoreloop(dot)com> wrote:

> Dear mailing-list,
>
> I am currently worried about an error that shows up in our log files since
> a few weeks:
>
> 2013-11-15 07:13:13 UTC [22668]: [2-1] ERROR: MultiXactId 2683601542 does
> no longer exist -- apparent wraparound
> 2013-11-15 07:13:13 UTC [22668]: [3-1] CONTEXT: automatic vacuum of table
> "scoreloop.public.gamer_device_sightings"
>
> It seems that "autovacuum" is active on that table, but it seems to have
> restarted today in the morning:
>
> select query_start, query, state, pid from pg_stat_activity where query
> LIKE 'autovacuum%' ;
>
> XXX=# select query_start, query, state, pid from pg_stat_activity where
> query LIKE 'autovacuum%' ;
>
> query_start | query
> | state | pid
>
> -------------------------------+----------------------------------------------------------------------------------+--------+------
> 2013-11-15 07:13:13.281202+00 | autovacuum: VACUUM ANALYZE
> public.gamer_device_sightings (to prevent wraparound) | active | 4360
>