From a0f5954af19ddcfea946b15744f2006a789dc4bd Mon Sep 17 00:00:00 2001 From: Andres Freund Date: Sun, 15 Mar 2015 17:37:07 +0100 Subject: [PATCH] Increase max_wal_size's default from 128MB to 1GB. The introduction of min_wal_size & max_wal_size in 88e982302684 makes it feasible to increase the default upper bound in checkpoint size. Previously raising the default would lead to a increased disk footprint, even if more segments weren't beneficial. The low default of checkpoint size is one of common performance problem users have thus increasing the default makes sense. Setups where the increase in maximum disk usage is a problem will very likely have to run with a modified configuration anyway. Discussion: 54F4EFB8.40202@agliodbs.com, CA+TgmoZEAgX5oMGJOHVj8L7XOkAe05Gnf45rP40m-K3FhZRVKg@mail.gmail.com Author: Josh Berkus, after a discussion involving lots of people. --- doc/src/sgml/config.sgml | 2 +- doc/src/sgml/wal.sgml | 2 +- src/backend/access/transam/xlog.c | 2 +- src/backend/utils/misc/guc.c | 2 +- src/backend/utils/misc/postgresql.conf.sample | 2 +- 5 files changed, 5 insertions(+), 5 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index d0f43c64af..b30c68dc13 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -2430,7 +2430,7 @@ include_dir 'conf.d' checkpoints. This is a soft limit; WAL size can exceed max_wal_size under special circumstances, like under heavy load, a failing archive_command, or a high - wal_keep_segments setting. The default is 128 MB. + wal_keep_segments setting. The default is 1 GB. Increasing this parameter can increase the amount of time needed for crash recovery. This parameter can only be set in the postgresql.conf diff --git a/doc/src/sgml/wal.sgml b/doc/src/sgml/wal.sgml index b57749fdbc..f4083c3fe5 100644 --- a/doc/src/sgml/wal.sgml +++ b/doc/src/sgml/wal.sgml @@ -475,7 +475,7 @@ linkend="guc-checkpoint-timeout"> seconds, or if is about to be exceeded, whichever comes first. - The default settings are 5 minutes and 128 MB, respectively. + The default settings are 5 minutes and 1 GB, respectively. If no WAL has been written since the previous checkpoint, new checkpoints will be skipped even if checkpoint_timeout has passed. (If WAL archiving is being used and you want to put a lower limit on how diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c index 17bd5d85a9..72af2c4330 100644 --- a/src/backend/access/transam/xlog.c +++ b/src/backend/access/transam/xlog.c @@ -79,7 +79,7 @@ extern uint32 bootstrap_data_checksum_version; /* User-settable parameters */ -int max_wal_size = 8; /* 128 MB */ +int max_wal_size = 64; /* 1 GB */ int min_wal_size = 5; /* 80 MB */ int wal_keep_segments = 0; int XLOGbuffers = -1; diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c index 7196b0b215..26275bda12 100644 --- a/src/backend/utils/misc/guc.c +++ b/src/backend/utils/misc/guc.c @@ -2191,7 +2191,7 @@ static struct config_int ConfigureNamesInt[] = GUC_UNIT_XSEGS }, &max_wal_size, - 8, 2, INT_MAX, + 64, 2, INT_MAX, NULL, assign_max_wal_size, NULL }, diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index d7a61f1fc4..110983f176 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -199,7 +199,7 @@ # - Checkpoints - #checkpoint_timeout = 5min # range 30s-1h -#max_wal_size = 128MB # in logfile segments +#max_wal_size = 1GB #min_wal_size = 80MB #checkpoint_completion_target = 0.5 # checkpoint target duration, 0.0 - 1.0 #checkpoint_warning = 30s # 0 disables -- 2.40.0