Re: Logical Replication speed-up initial data

On Thu, 5 Aug 2021 at 10:27, Nikhil Shetty <nikhil(dot)dba04(at)gmail(dot)com> wrote:

> Hi,
>
> Thank you for the suggestion.
>
> We tried by dropping indexes and it worked faster compared to what we saw
> earlier. We wanted to know if anybody has done any other changes that helps
> speed-up initial data load without dropping indexes.
>
>
PS: i have not tested this in production level loads, it was just some exp
i did on my laptop.

one option would be to use pglogical extension (this was shared by
Dharmendra in one the previous mails, sharing the same),
and then use pglogical_create_subscriber cli to create the initial copy via
pgbasebackup and then carry on from there.
I ran the test case similar to one below in my local env, and it seems to
work fine. of course i do not have TB worth of load to test, but it looks
promising,
especially since they introduced it to the core.
pglogical/010_pglogical_create_subscriber.pl at REL2_x_STABLE ·
2ndQuadrant/pglogical (github.com)
<https://github.com/2ndQuadrant/pglogical/blob/REL2_x_STABLE/t/010_pglogical_create_subscriber.pl>
Once you attain some reasonable sync state, you can drop the pglogical
extension, and check if things continue fine.
I have done something similar when upgrading from 9.6 to 11 using pglogical
and then dropping the extension and it was smooth,
maybe you need to try this out and share if things works fine.
and
The 1-2-3 for PostgreSQL Logical Replication Using an RDS Snapshot -
Percona Database Performance Blog
<https://www.percona.com/blog/postgresql-logical-replication-using-an-rds-snapshot/>