Re: Wal file query

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.
>