Re: wal exist in slave but getting err requested WAL segment has already been removed

On 11/07/2018 16:09, Mariel Cherkassky wrote:
> Hi,
> I have in my cluster 3 nodes (1 master version 9.6.3+ 2 slaves version 9.6.3). I configured repmgr (with repmgrd active) v 4.0.4.
>
> Suddenly today after a few good weeks I noticed that there is a lag in one of the slaves and the error in the log indicated that the slave didnt get the wal :
>
> could not receive data from WAL stream: ERROR: requested WAL segment 0000000900002E61000000BD has already been removed
>
> However, when I check if the wal was recieveed :
> postgres=# select pg_is_in_recovery(),pg_is_xlog_replay_paused(),pg_last_xlog_receive_location(),pg_last_xlog_replay_location();
>  pg_is_in_recovery | pg_is_xlog_replay_paused | pg_last_xlog_receive_location | pg_last_xlog_replay_location
> -------------------+--------------------------+-------------------------------+------------------------------
>  t                 | f                        | 2E61/BDF5C000                 | 2E61/BDF5B930
> (1 row)
>
> and  I checked in pg_xlog directory :
> ls -l ../pg_xlog/0000000900002E61000000BD
> -rw------- 1 postgres postgres 16777216 Jul 11 11:13 ../pg_xlog/0000000900002E61000000BD
>
> and the xlog is exist.

In which node did you check for the file?
If the file in the primary is still available, try to compare their md5sum .
If you have a working WAL shipping method in place, then add the appropriate line in the recovery.conf of your standby :

restore_command = 'rsync somemachine:/somepath/pitr/%f "%p" '

> Now is my question, why the wal wasnt replayed ?
> In my repmgr.conf I dont have any parameters regarding recovery just some basic things.  The recovery.conf file in the data directory :
>
> standby_mode = 'on'
> primary_conninfo = 'host=xxxxxxx user=repmgr application_name=''psgsqldb2'' connect_timeout=2'
> recovery_target_timeline = 'latest'
>
>
> any idea ?

--
Achilleas Mantzios
IT DEV Lead
IT DEPT
Dynacom Tankers Mgmt