Date: Mon, 15 Oct 2018 22:26:07 -0700 (MST)
From: pavan95 <pavan.postgresdba@gmail.com>
To: pgsql-admin@postgresql.org
Message-ID: <1539667567051-0.post@n3.nabble.com>
In-Reply-To: <81cfab86-c6dc-89a1-5685-7589e4f81f9d@catalyst.net.nz>
References: <1539447741900-0.post@n3.nabble.com>
 <20427d4e-98a5-0cda-bddc-070989015cca@catalyst.net.nz>
 <1539598263562-0.post@n3.nabble.com>
 <81cfab86-c6dc-89a1-5685-7589e4f81f9d@catalyst.net.nz>
Subject: Re: Hick ups in Postgresql Logical Replication
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>With respect to the question about wal files and LSN, see the function
pg_walfile_name(), e.g: 

>postgres=# SELECT pg_current_wal_lsn(); 
>  pg_current_wal_lsn 
>-------------------- 
>  0/51EB3BA8 
>(1 row) 

>postgres=# SELECT pg_walfile_name(pg_current_wal_lsn()); 
>      pg_walfile_name 
>-------------------------- 
>  000000010000000000000051 
>(1 row) 

Hi Mark,

My question was like how to get all the LSN's that are available in a WAL
segment. For example, take a segment named "000000010000000000000051". 

So in the above archive log segment, how to get all the LSN's of all txn's
which belong to that segment ?

*The idea for asking this is, I will get the remote_lsn on the subscriber
which was successfully applied from the view "pg_replication_origin_status".

Based on the LSN, I will check in which archive segment that particular LSN
is present(as you said above). 

And will find all the later LSN's(later to remote_lsn). 

So I can say that these many transactions are yet to be applied to the
target.*

Regards,
Pavan,
9841380956


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