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5509055d69
This patch introduces sequence synchronization. Sequences that are synced
will have 2 states:
- INIT (needs [re]synchronizing)
- READY (is already synchronized)
A new sequencesync worker is launched as needed to synchronize sequences.
A single sequencesync worker is responsible for synchronizing all
sequences. It begins by retrieving the list of sequences that are flagged
for synchronization, i.e., those in the INIT state. These sequences are
then processed in batches, allowing multiple entries to be synchronized
within a single transaction. The worker fetches the current sequence
values and page LSNs from the remote publisher, updates the corresponding
sequences on the local subscriber, and finally marks each sequence as
READY upon successful synchronization.
Sequence synchronization occurs in 3 places:
1) CREATE SUBSCRIPTION
- The command syntax remains unchanged.
- The subscriber retrieves sequences associated with publications.
- Published sequences are added to pg_subscription_rel with INIT
state.
- Initiate the sequencesync worker to synchronize all sequences.
2) ALTER SUBSCRIPTION ... REFRESH PUBLICATION
- The command syntax remains unchanged.
- Dropped published sequences are removed from pg_subscription_rel.
- Newly published sequences are added to pg_subscription_rel with INIT
state.
- Initiate the sequencesync worker to synchronize only newly added
sequences.
3) ALTER SUBSCRIPTION ... REFRESH SEQUENCES
- A new command introduced for PG19 by f0b3573c3a.
- All sequences in pg_subscription_rel are reset to INIT state.
- Initiate the sequencesync worker to synchronize all sequences.
- Unlike "ALTER SUBSCRIPTION ... REFRESH PUBLICATION" command,
addition and removal of missing sequences will not be done in this
case.
Author: Vignesh C <vignesh21@gmail.com>
Reviewed-by: shveta malik <shveta.malik@gmail.com>
Reviewed-by: Hou Zhijie <houzj.fnst@fujitsu.com>
Reviewed-by: Masahiko Sawada <sawada.mshk@gmail.com>
Reviewed-by: Hayato Kuroda <kuroda.hayato@fujitsu.com>
Reviewed-by: Dilip Kumar <dilipbalaut@gmail.com>
Reviewed-by: Peter Smith <smithpb2250@gmail.com>
Reviewed-by: Nisha Moond <nisha.moond412@gmail.com>
Reviewed-by: Shlok Kyal <shlok.kyal.oss@gmail.com>
Reviewed-by: Amit Kapila <amit.kapila16@gmail.com>
Reviewed-by: Chao Li <li.evan.chao@gmail.com>
Discussion: https://postgr.es/m/CAA4eK1LC+KJiAkSrpE_NwvNdidw9F2os7GERUeSxSKv71gXysQ@mail.gmail.com
62 lines
2.8 KiB
C
62 lines
2.8 KiB
C
/*-------------------------------------------------------------------------
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*
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* catversion.h
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* "Catalog version number" for PostgreSQL.
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*
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* The catalog version number is used to flag incompatible changes in
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* the PostgreSQL system catalogs. Whenever anyone changes the format of
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* a system catalog relation, or adds, deletes, or modifies standard
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* catalog entries in such a way that an updated backend wouldn't work
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* with an old database (or vice versa), the catalog version number
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* should be changed. The version number stored in pg_control by initdb
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* is checked against the version number compiled into the backend at
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* startup time, so that a backend can refuse to run in an incompatible
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* database.
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*
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* The point of this feature is to provide a finer grain of compatibility
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* checking than is possible from looking at the major version number
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* stored in PG_VERSION. It shouldn't matter to end users, but during
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* development cycles we usually make quite a few incompatible changes
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* to the contents of the system catalogs, and we don't want to bump the
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* major version number for each one. What we can do instead is bump
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* this internal version number. This should save some grief for
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* developers who might otherwise waste time tracking down "bugs" that
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* are really just code-vs-database incompatibilities.
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*
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* The rule for developers is: if you commit a change that requires
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* an initdb, you should update the catalog version number (as well as
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* notifying the pgsql-hackers mailing list, which has been the
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* informal practice for a long time).
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*
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* The catalog version number is placed here since modifying files in
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* include/catalog is the most common kind of initdb-forcing change.
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* But it could be used to protect any kind of incompatible change in
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* database contents or layout, such as altering tuple headers.
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* Another common reason for a catversion update is a change in parsetree
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* external representation, since serialized parsetrees appear in stored
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* rules and new-style SQL functions. Almost any change in primnodes.h or
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* parsenodes.h will warrant a catversion update.
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*
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*
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* Portions Copyright (c) 1996-2025, PostgreSQL Global Development Group
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* Portions Copyright (c) 1994, Regents of the University of California
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*
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* src/include/catalog/catversion.h
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*
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*-------------------------------------------------------------------------
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*/
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#ifndef CATVERSION_H
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#define CATVERSION_H
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/*
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* We could use anything we wanted for version numbers, but I recommend
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* following the "YYYYMMDDN" style often used for DNS zone serial numbers.
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* YYYYMMDD are the date of the change, and N is the number of the change
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* on that day. (Hopefully we'll never commit ten independent sets of
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* catalog changes on the same day...)
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*/
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/* yyyymmddN */
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#define CATALOG_VERSION_NO 202511051
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#endif
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