Re: Minimal logical decoding on standbys

Andres Freund <andres@anarazel.de>

From: Andres Freund <andres@anarazel.de>

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

Cc: tushar <tushar.ahuja@enterprisedb.com>, Petr Jelinek <petr.jelinek@2ndquadrant.com>, Robert Haas <robertmhaas@gmail.com>, Craig Ringer <craig@2ndquadrant.com>, Petr Jelinek <petr@2ndquadrant.com>, pgsql-hackers <pgsql-hackers@postgresql.org>

Date: 2019-06-04T15:58:53Z

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

Hi,

On 2019-06-04 15:51:01 +0530, Amit Khandekar wrote:
> After giving more thought on this, I think it might make sense to
> arrange for the xl_running_xact record to be sent from master to the
> standby, when a logical slot is to be created on standby. How about
> standby sending a new message type to the master, requesting for
> xl_running_xact record ? Then on master, ProcessStandbyMessage() will
> process this new message type and call LogStandbySnapshot().

I think that should be a secondary feature. You don't necessarily know
the upstream master, as the setup could be cascading one. I think for
now just having to wait, perhaps with a comment to manually start a
checkpoint, ought to suffice?

Greetings,

Andres Freund