Horton

Re: Minimal logical decoding on standbys

Jeff Davis <pgsql@j-davis.com>

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From: Jeff Davis <pgsql@j-davis.com>
To: Andres Freund <andres@anarazel.de>
Cc: "Drouvot, Bertrand" <bertranddrouvot.pg@gmail.com>, 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: 2023-04-02T23:04:42Z
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.

On Sun, 2023-04-02 at 15:29 -0700, Andres Freund wrote:
> I agree that the *wait* has to go through condition_variable.c, but
> it doesn't
> seem right that creation of the WES needs to go through
> condition_variable.c.

The kind of WES required by a CV is an implementation detail, so I was
concerned about making too many assumptions across different APIs.

But what I ended up with is arguably not better, so perhaps I should do
it your way and then just have some comments about what assumptions are
being made?

> The only thing that ConditionVariableEventSleep() seems to require is
> that the
> WES is waiting for MyLatch. You don't even need a separate WES for
> that, the
> already existing WES should suffice.

By "already existing" WES, I assume you mean FeBeWaitSet? Yes, that
mostly matches, but it uses WL_POSTMASTER_DEATH instead of
WL_EXIT_ON_PM_DEATH, so I'd need to handle PM death in
condition_variable.c. That's trivial to do, though.

Regards,
	Jeff Davis