Re: Minimal logical decoding on standbys

Amit Khandekar <amitdkhan.pg@gmail.com>

From: Amit Khandekar <amitdkhan.pg@gmail.com>

To: Rahila Syed <rahila.syed@2ndquadrant.com>

Cc: pgsql-hackers <pgsql-hackers@postgresql.org>

Date: 2019-11-08T05:01:33Z

Lists: pgsql-hackers

Commits

Same data as JSON: GET /api/v1/messages/:b64id/commits the thread's linked commits as JSON, with link sources. API reference →

Reduce the log level in 035_standby_logical_decoding.pl.
- 3034dc56ef4b 16.0 landed
035_standby_logical_decoding: Add missing waits for replication
- 57411c82ce86 16.0 landed
For cascading replication, wake physical and logical walsenders separately
- e101dfac3a53 16.0 landed
Handle logical slot conflicts on standby
- 26669757b6a7 16.0 landed
Support invalidating replication slots due to horizon and wal_level
- be87200efd93 16.0 landed
Prevent use of invalidated logical slot in CreateDecodingContext()
- 4397abd0a2af 16.0 landed
Replace replication slot's invalidated_at LSN with an enum
- 15f8203a5975 16.0 landed
Pass down table relation into more index relation functions
- 61b313e47eb9 16.0 landed
Assert only valid flag bits are passed to visibilitymap_set()
- a88a18b1250b 16.0 landed
Remove unused _bt_delitems_delete() argument.
- dc43492e46c7 14.0 cited
Add xl_btree_delete optimization.
- d2e5e20e5711 13.0 cited

On Thu, 7 Nov 2019 at 14:02, Rahila Syed <rahila.syed@2ndquadrant.com> wrote:
>
> Hi Amit,
>
> I am reading about this feature and reviewing it.
> To start with, I reviewed the patch: 0005-Doc-changes-describing-details-about-logical-decodin.patch.

Thanks for picking up the patch review.

Your reply somehow spawned a new mail thread, so I reverted back to
this thread for replying.

>
> >prevent VACUUM from removing required rows from the system catalogs,
> >hot_standby_feedback should be set on the standby. In spite of that,
> >if any required rows get removed on standby, the slot gets dropped.
> IIUC, you mean `if any required rows get removed on *the master* the slot gets
> dropped`, right?

Yes, you are right. In fact, I think it is not necessary to explicitly
mention where the rows get removed. So I have just omitted "on
standby". Will include this change in the next patch versions.

-- 
Thanks,
-Amit Khandekar
EnterpriseDB Corporation
The Postgres Database Company