Subject: Re: Minimal logical decoding on standbys
To: Andres Freund <andres@anarazel.de>
Cc: Petr Jelinek <petr.jelinek@2ndquadrant.com>,
 Robert Haas <robertmhaas@gmail.com>, Craig Ringer <craig@2ndquadrant.com>,
 Petr Jelinek <petr@2ndquadrant.com>, pgsql-hackers@postgresql.org
References: <20181212204154.nsxf3gzqv3gesl32@alap3.anarazel.de>
 <7e905539-7fdc-6b29-5a56-ba48d180fef8@2ndquadrant.com>
 <cbda32d2-eeb6-31b9-a88a-566330a46fc4@enterprisedb.com>
 <20190301174628.rjzoi7arvci5ldcm@alap3.anarazel.de>
 <aeb9759c-ef7b-6a3b-13ad-0709e52726d5@enterprisedb.com>
 <20190304172739.hdkwmtngwx5444un@alap3.anarazel.de>
From: tushar <tushar.ahuja@enterprisedb.com>
Message-ID: <9fce660d-47fc-4294-3084-3769e543da8a@enterprisedb.com>
Date: Thu, 7 Mar 2019 21:03:51 +0530
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There is an another issue , where i am getting error while executing 
"pg_logical_slot_get_changes" on SLAVE

Master (running on port=5432) -  run "make installcheck"  after setting  
PATH=<installation/bin:$PATH )  and export PGDATABASE=postgres from 
regress/ folder
Slave (running on port=5555)  -  Connect to regression database and 
select pg_logical_slot_get_changes

[centos@mail-arts bin]$ ./psql postgres -p 5555 -f t.sql
You are now connected to database "regression" as user "centos".
  slot_name |    lsn
-----------+-----------
  m61       | 1/D437AD8
(1 row)

psql:t.sql:3: ERROR:  could not resolve cmin/cmax of catalog tuple

[centos@mail-arts bin]$ cat t.sql
\c regression
SELECT * from   pg_create_logical_replication_slot('m61', 'test_decoding');
select * from pg_logical_slot_get_changes('m61',null,null);

regards,

On 03/04/2019 10:57 PM, Andres Freund wrote:
> Hi,
>
> On 2019-03-04 16:54:32 +0530, tushar wrote:
>> On 03/01/2019 11:16 PM, Andres Freund wrote:
>>> So, if I understand correctly you do*not*  have a phyiscal replication
>>> slot for this standby? For the feature to work reliably that needs to
>>> exist, and you need to have hot_standby_feedback enabled. Does having
>>> that fix the issue?
>> Ok, This time around  - I performed like this -
>>
>> .)Master cluster (set wal_level=logical and hot_standby_feedback=on in
>> postgresql.conf) , start the server and create a physical replication slot
> Note that hot_standby_feedback=on needs to be set on a standby, not on
> the primary (although it doesn't do any harm there).
>
> Thanks,
>
> Andres
>

-- 
regards,tushar
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