Re: Wal file query

You cannot connect to the Primary while connected to the Replica, except
via postgres_fdw. Even then, it might not work, since the replica
replicates _fdw definitions.

These exist on the primary:

pg_current_wal_lsn()
pg_replication_slots
pg_stat_replication

These exist on the replica:

pg_last_wal_receive_lsn()
pg_last_wal_replay_lsn()
pg_stat_wal_receiver
pg_get_wal_replay_pause_state()

On Tue, Apr 8, 2025 at 9:09 AM Atul Kumar <akumar14871(at)gmail(dot)com> wrote:

> I got the error:
>
> Wal control functions cannot be executed during recovery.
>
> I need the solution that should in when streaming replication is
> configured.
>
> My postgres version is 13.20
>
>
> Regards.
>
> On Tue, 8 Apr 2025, 17:32 Kashif Zeeshan, <kashi(dot)zeeshan(at)gmail(dot)com> wrote:
>
>> Hi Atul
>>
>> Start by looking at the current WAL LSN and insert LSN. The
>> pg_current_wal_lsn is the location of the last write. The
>> pg_current_wal_insert_lsn is the logical location and reflects data in
>> the buffer that has not been written to disk. There is also a flush value
>> that shows what has been written to durable storage.
>>
>> [postgres] # select pg_current_wal_lsn(), pg_current_wal_insert_lsn();
>> pg_current_wal_lsn | pg_current_wal_insert_lsn
>> --------------------+---------------------------
>> 76/7D000000 | 76/7D000028
>> (1 row)
>>
>> Although you can guess the name of the WAL file based on the above output, it is best to use the pg_walfile_name function.
>>
>>
>> [postgres] # select pg_walfile_name('76/7D000028');
>> pg_walfile_name
>> --------------------------
>> 00000001000000760000007D
>> (1 row)
>>
>>
>> For details visit following link : https://www.crunchydata.com/blog/postgres-wal-files-and-sequuence-numbers
>>
>>
>> Thanks
>>
>> Kashif Zeeshan
>>
>>
>>
>> On Tue, Apr 8, 2025 at 4:44 PM Atul Kumar <akumar14871(at)gmail(dot)com> wrote:
>>
>>> In streaming replication What is the way to check which "WAL file" is
>>> currently in use in primary and in standby ?
>>>
>>>
>>> Regards.
>>>
>>

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