Re: Stuck Checkpoint Process

Hi Team,

Any assist here would be helpful

Thanks,
Nikhil

On Wed, 3 Nov 2021 at 2:47 PM, Nikhil Shetty <nikhil(dot)dba04(at)gmail(dot)com> wrote:

> Hi Team,
>
> PostgreSQL Version - 11.7
> OS - RHEL 7.9
>
> Problem:
> We see that the backups were not happening on one of the instances. On
> further checking, we saw that the checkpoint process was not working. Last
> checkpoint was 7 days ago. Manual checkpoint goes into hang state.
>
> Checkpoint Process
>
>> > pid | backend_start | wait_event_type |
>> wait_event | backend_type
>> >
>> -------+-------------------------------+-----------------+---------------------+--------------
>> > 21237 | 2021-06-29 21:27:51.806746+00 | LWLock |
>> replication_slot_io | checkpointer
>> > (1 row)
>
>
> Time of latest checkpoint: Wed 27 Oct 2021 03:45:09 PM PDT
>
> I see it is waiting for I/O on replication slots. I see no issue on
> standby and replication is working fine. Need help to further debug this
>
> Replication Slots
>
>> > dbname=# select pg_current_wal_lsn();
>> > pg_current_wal_lsn
>> > --------------------
>> > 2B0/75042DE0
>>
>> > dbname=# select * from pg_replication_slots ;
>> > slot_name | plugin | slot_type | datoid | database | temporary |
>> active | active_pid | xmin | catalog_xmin | restart_lsn |
>> confirmed_flush_lsn
>> >
>> ---------------+--------+-----------+--------+----------+-----------+--------+------------+------+--------------+--------------+---------------------
>> > repmgr_slot_5 | | physical | | | f | t
>> | 4285 | | | 2B0/75042DE0 |
>> > repmgr_slot_1 | | physical | | | f | t
>> | 3402 | | | 2B0/75042DE0 |
>>
>
> Thanks and Regards,
> Nikhil
>