Re: Minimal logical decoding on standbys

Bertrand Drouvot <bertranddrouvot.pg@gmail.com>

From: "Drouvot, Bertrand" <bertranddrouvot.pg@gmail.com>

To: Andres Freund <andres@anarazel.de>

Cc: Robert Haas <robertmhaas@gmail.com>, Thomas Munro <thomas.munro@gmail.com>, Alvaro Herrera <alvherre@2ndquadrant.com>, Ibrar Ahmed <ibrar.ahmad@gmail.com>, Amit Khandekar <amitdkhan.pg@gmail.com>, fabriziomello@gmail.com, tushar <tushar.ahuja@enterprisedb.com>, Rahila Syed <rahila.syed@2ndquadrant.com>, pgsql-hackers <pgsql-hackers@postgresql.org>

Date: 2023-02-07T15:29:07Z

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

Attachments

v49-0006-Doc-changes-describing-details-about-logical-dec.patch (text/plain) patch v49-0006
v49-0005-New-TAP-test-for-logical-decoding-on-standby.patch (text/plain) patch v49-0005
v49-0004-Fixing-Walsender-corner-case-with-logical-decodi.patch (text/plain) patch v49-0004
v49-0003-Allow-logical-decoding-on-standby.patch (text/plain) patch v49-0003
v49-0002-Handle-logical-slot-conflicts-on-standby.patch (text/plain) patch v49-0002
v49-0001-Add-info-in-WAL-records-in-preparation-for-logic.patch (text/plain) patch v49-0001

Hi,

On 1/19/23 10:43 AM, Drouvot, Bertrand wrote:
> Hi,
> 
> On 1/19/23 3:46 AM, Andres Freund wrote:
>> Hi,
>>
>> On 2023-01-18 11:24:19 +0100, Drouvot, Bertrand wrote:
>>> On 1/6/23 4:40 AM, Andres Freund wrote:
>>>> Hm, that's quite expensive. Perhaps worth adding a C helper that can do that
>>>> for us instead? This will likely also be needed in real applications after all.
>>>>
>>>
>>> Not sure I got it. What the C helper would be supposed to do?
>>
>> Call LogStandbySnapshot().
>>
> 
> Got it, I like the idea, will do.
> 

0005 in V49 attached is introducing a new pg_log_standby_snapshot() function
and the TAP test is making use of it.

Documentation about this new function is also added in the "Snapshot Synchronization Functions"
section. I'm not sure that's the best place for it but did not find a better place yet.

Regards,

-- 
Bertrand Drouvot
PostgreSQL Contributors Team
RDS Open Source Databases
Amazon Web Services: https://aws.amazon.com