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Tom Lane 66c2922e76 Take care to de-duplicate entries in standby.c's table of locks.
The RecoveryLockLists data structure, which tracks all exclusive
locks that the startup process is holding on behalf of transactions
being replayed, did not have any provision for avoiding duplicate
entries for the same lock.  Maybe that was okay when the code was
first written.  However, modern practice is for checkpoints to
write fresh lists of all active exclusive locks into the WAL.
Thus, an exclusive lock that survives across multiple checkpoints
causes bloat in standbys' startup processes.  If there are a lot
of such locks this can look like a memory leak, and it's even
possible to drive the startup process into a palloc failure from
an over-length List.

To fix, use a hash table instead of simple lists to track the
locks being held.  Allowing for dynahash overhead, this requires
a little more space per lock than the old way (although it's the
same size as what we were allocating prior to c6e0fe1f2).  It's
probably a shade slower too.  However, testing indicates that the
penalty is negligible on ordinary workloads, so let's make this
change to improve robustness in extreme cases.

Patch by me, per report from Dmitriy Kuzmin.  No back-patch
(for now anyway), since it seems that a significant improvement
would only occur in corner cases.

Discussion: https://postgr.es/m/CAHLDt=_ts0A7Agn=hCpUh+RCFkxd+G6uuT=kcTfqFtGur0dp=A@mail.gmail.com
2022-10-06 12:27:36 -04:00
config meson: Add initial version of meson based build system 2022-09-21 22:37:17 -07:00
contrib Remove useless character-length checks in contrib/ltree. 2022-10-06 11:18:32 -04:00
doc doc: clarify description for log_startup_progress_interval 2022-10-05 15:53:40 -04:00
src Take care to de-duplicate entries in standby.c's table of locks. 2022-10-06 12:27:36 -04:00
.cirrus.yml ci: enable various runtime checks on FreeBSD and macOS 2022-10-01 17:39:53 -07:00
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.gitignore Support for optimizing and emitting code in LLVM JIT provider. 2018-03-22 11:05:22 -07:00
aclocal.m4
configure meson: Add initial version of meson based build system 2022-09-21 22:37:17 -07:00
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COPYRIGHT Update copyright for 2022 2022-01-07 19:04:57 -05:00
GNUmakefile.in Run tests of libpq on installcheck-world, checkprep and check-world 2022-06-03 13:15:20 +09:00
HISTORY
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README
README.git Canonicalize some URLs 2020-02-10 20:47:50 +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.

PostgreSQL has many language interfaces, many of which are listed here:

	https://www.postgresql.org/download/

See the file INSTALL for instructions on how to build and install
PostgreSQL.  That file also lists supported operating systems and
hardware platforms and contains information regarding any other
software packages that are required to build or run the PostgreSQL
system.  Copyright and license information can be found in the
file COPYRIGHT.  A comprehensive documentation set is included in this
distribution; it can be read as described in the installation
instructions.

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