Alexander Korotkov 06c418e163 Implement pg_wal_replay_wait() stored procedure
pg_wal_replay_wait() is to be used on standby and specifies waiting for
the specific WAL location to be replayed before starting the transaction.
This option is useful when the user makes some data changes on primary and
needs a guarantee to see these changes on standby.

The queue of waiters is stored in the shared memory array sorted by LSN.
During replay of WAL waiters whose LSNs are already replayed are deleted from
the shared memory array and woken up by setting of their latches.

pg_wal_replay_wait() needs to wait without any snapshot held.  Otherwise,
the snapshot could prevent the replay of WAL records implying a kind of
self-deadlock.  This is why it is only possible to implement
pg_wal_replay_wait() as a procedure working in a non-atomic context,
not a function.

Catversion is bumped.

Discussion: https://postgr.es/m/eb12f9b03851bb2583adab5df9579b4b%40postgrespro.ru
Author: Kartyshov Ivan, Alexander Korotkov
Reviewed-by: Michael Paquier, Peter Eisentraut, Dilip Kumar, Amit Kapila
Reviewed-by: Alexander Lakhin, Bharath Rupireddy, Euler Taveira
2024-04-02 22:48:03 +03:00
2024-02-28 15:17:23 +04:00
2024-04-03 00:57:34 +13:00
2022-12-04 15:23:00 -05:00
2024-01-03 20:49:05 -05:00
2024-03-25 06:29:53 +01:00
2024-02-28 15:17:23 +04:00
2024-03-25 06:29:53 +01:00

PostgreSQL Database Management System

This directory contains the source code distribution of the PostgreSQL database management system.

PostgreSQL is an advanced object-relational database management system that supports an extended subset of the SQL standard, including transactions, foreign keys, subqueries, triggers, user-defined types and functions. This distribution also contains C language bindings.

Copyright and license information can be found in the file COPYRIGHT.

General documentation about this version of PostgreSQL can be found at https://www.postgresql.org/docs/devel/. In particular, information about building PostgreSQL from the source code can be found at https://www.postgresql.org/docs/devel/installation.html.

The latest version of this software, and related software, may be obtained at https://www.postgresql.org/download/. For more information look at our web site located at https://www.postgresql.org/.

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Mirror of the official PostgreSQL GIT repository. Note that this is just a *mirror* - we don't work with pull requests on github. To contribute, please see https://wiki.postgresql.org/wiki/Submitting_a_Patch
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