Horton

Re: Minimal logical decoding on standbys

Bertrand Drouvot <bertranddrouvot.pg@gmail.com>

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From: "Drouvot, Bertrand" <bertranddrouvot.pg@gmail.com>
To: Masahiko Sawada <sawada.mshk@gmail.com>
Cc: Amit Kapila <amit.kapila16@gmail.com>, Jeff Davis <pgsql@j-davis.com>, Andres Freund <andres@anarazel.de>, 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: 2023-04-04T09:47:46Z
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 →

  1. Reduce the log level in 035_standby_logical_decoding.pl.

  2. 035_standby_logical_decoding: Add missing waits for replication

  3. For cascading replication, wake physical and logical walsenders separately

  4. Handle logical slot conflicts on standby

  5. Support invalidating replication slots due to horizon and wal_level

  6. Prevent use of invalidated logical slot in CreateDecodingContext()

  7. Replace replication slot's invalidated_at LSN with an enum

  8. Pass down table relation into more index relation functions

  9. Assert only valid flag bits are passed to visibilitymap_set()

  10. Remove unused _bt_delitems_delete() argument.

  11. Add xl_btree_delete optimization.

Hi,

On 4/4/23 9:48 AM, Masahiko Sawada wrote:
> On Tue, Apr 4, 2023 at 10:55 AM Masahiko Sawada <sawada.mshk@gmail.com> wrote:
>>
>>
>> Regarding 0004 patch:
>>
>> @@ -2626,6 +2626,12 @@ InitWalSenderSlot(void)
>>                          walsnd->sync_standby_priority = 0;
>>                          walsnd->latch = &MyProc->procLatch;
>>                          walsnd->replyTime = 0;
>> +
>> +                       if (MyDatabaseId == InvalidOid)
>> +                               walsnd->kind = REPLICATION_KIND_PHYSICAL;
>> +                       else
>> +                               walsnd->kind = REPLICATION_KIND_LOGICAL;
>> +
>>
>> I think we might want to set the replication kind when processing the
>> START_REPLICATION command. The walsender using a logical replication
>> slot is not necessarily streaming (e.g. when COPYing table data).
>>
> 
> Discussing with Bertrand off-list, it's wrong as the logical
> replication slot creation also needs to read WAL records so a
> walsender who is creating a logical replication slot needs to be woken
> up. We can set it the replication kind when processing
> START_REPLICATION and CREATE_REPLICATION_SLOT, but it seems better to
> set it in one place. So I agree to set it in InitWalSenderSlot().
> 

Thanks for the review and feedback!
Added a comment in 0004 in V58 just posted up-thread to explain the reason
why the walsnd->kind assignment is done InitWalSenderSlot().

Regards,

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