Re: logical Replication

> Hi Achilleas,
>
>> Now on the publisher side what does :
>> select * from pg_stat_replication ;
>> tell you?
> Please find the below output:
>> *select * from pg_stat_replication ;*
> pid | usesysid | usename | application_name | client_addr |
> client_hostname | client_port | backend_start |
> backend_xmin | state | sent_lsn | write_lsn | flush_lsn |
> replay_lsn
> | write_lag | flush_lag | replay_lag | sync_priority | sync_state
> -------+----------+----------+------------------+--------------+-----------------+-------------+----------------------------------+--------------+-----------+------------+------------+------------+------------+-----------+-----------+------------+---------------+------------
> 32515 | 78225 | user | appn | xxx.xxx.xx.xxx |
> | 411111 | 2018-08-20 11:32:09.636622+05:30 | |
> streaming
> | 0/69BE27D0 | 0/69BE27D0 | 0/69BE27D0 | 0/69BE27D0 | |
> | | 0 | async
>
>>So here you have zero lag. How do you experience the lag? What do you
exactly measure?

Actually there are no running transactions in the database. When I insert
the data suppose 100 records in a table and after commit connect to the
subscriber database and issue row count from that particular table, I am
finding that the data didn't got replicated.

Later which I will proceed with :
ALTER SUBSCRIPTION my_sub_name WITH REFRESH PUBLICATION WITH( COPY_DATA)

Even then I can't see the data replicated in the subscriber side.

Then I will go with dropping and recreating the SUBSCRIPTION on the
subscriber side where I will see that inserted 100 records in the subscriber
side.

Again will try inserting another 1000 records which will get replicated
within microsecond(I guess).

This is what I will consider as lag. Hope I answered your question.

Looking forward to hear from you.

Regards,
Pavan

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