From 692c0727d84d534a2575e0442c96e4df3752a7b4 Mon Sep 17 00:00:00 2001 From: Heikki Linnakangas Date: Wed, 1 Apr 2026 00:09:35 +0300 Subject: [PATCH v3 4/4] Change default max_locks_per_transactions=128 --- doc/src/sgml/config.sgml | 2 +- src/backend/utils/init/postinit.c | 2 +- src/backend/utils/misc/guc_parameters.dat | 2 +- src/backend/utils/misc/postgresql.conf.sample | 2 +- src/bin/pg_resetwal/pg_resetwal.c | 4 ++-- 5 files changed, 6 insertions(+), 6 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 229f41353eb..20706b56158 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -11470,7 +11470,7 @@ dynamic_library_path = '/usr/local/lib/postgresql:$libdir' can lock more objects as long as the locks of all transactions fit in the lock table. This is not the number of rows that can be locked; that value is unlimited. The default, - 64, has historically proven sufficient, but you might need to + 128, has historically proven sufficient, but you might need to raise this value if you have queries that touch many different tables in a single transaction, e.g., query of a parent table with many children. This parameter can only be set at server start. diff --git a/src/backend/utils/init/postinit.c b/src/backend/utils/init/postinit.c index 577ef5effbb..783a7400464 100644 --- a/src/backend/utils/init/postinit.c +++ b/src/backend/utils/init/postinit.c @@ -593,7 +593,7 @@ InitializeFastPathLocks(void) * value at FP_LOCK_GROUPS_PER_BACKEND_MAX and insist the value is at * least 1. * - * The default max_locks_per_transaction = 64 means 4 groups by default. + * The default max_locks_per_transaction = 128 means 8 groups by default. */ FastPathLockGroupsPerBackend = Max(Min(pg_nextpower2_32(max_locks_per_xact) / FP_LOCK_SLOTS_PER_GROUP, diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat index 0a862693fcd..a3e0dda34af 100644 --- a/src/backend/utils/misc/guc_parameters.dat +++ b/src/backend/utils/misc/guc_parameters.dat @@ -1979,7 +1979,7 @@ short_desc => 'Sets the maximum number of locks per transaction.', long_desc => 'The shared lock table is sized on the assumption that at most "max_locks_per_transaction" objects per server process or prepared transaction will need to be locked at any one time.', variable => 'max_locks_per_xact', - boot_val => '64', + boot_val => '128', min => '10', max => 'INT_MAX', }, diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index cf15597385b..6e376d85d61 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -856,7 +856,7 @@ #------------------------------------------------------------------------------ #deadlock_timeout = 1s -#max_locks_per_transaction = 64 # min 10 +#max_locks_per_transaction = 128 # min 10 # (change requires restart) #max_pred_locks_per_transaction = 64 # min 10 # (change requires restart) diff --git a/src/bin/pg_resetwal/pg_resetwal.c b/src/bin/pg_resetwal/pg_resetwal.c index ab766c34d4b..44f2b446e5d 100644 --- a/src/bin/pg_resetwal/pg_resetwal.c +++ b/src/bin/pg_resetwal/pg_resetwal.c @@ -722,7 +722,7 @@ GuessControlValues(void) ControlFile.max_wal_senders = 10; ControlFile.max_worker_processes = 8; ControlFile.max_prepared_xacts = 0; - ControlFile.max_locks_per_xact = 64; + ControlFile.max_locks_per_xact = 128; ControlFile.maxAlign = MAXIMUM_ALIGNOF; ControlFile.floatFormat = FLOATFORMAT_VALUE; @@ -931,7 +931,7 @@ RewriteControlFile(void) ControlFile.max_wal_senders = 10; ControlFile.max_worker_processes = 8; ControlFile.max_prepared_xacts = 0; - ControlFile.max_locks_per_xact = 64; + ControlFile.max_locks_per_xact = 128; /* The control file gets flushed here. */ update_controlfile(".", &ControlFile, true); -- 2.47.3