From 8f91d87d43d021db92c6edd966a4bb8c3a81ae39 Mon Sep 17 00:00:00 2001
From: Andres Freund <andres@anarazel.de>
Date: Sun, 24 Apr 2016 12:26:55 -0700
Subject: [PATCH] Fix documentation & config inconsistencies around 428b1d6b2.
Several issues:
1) checkpoint_flush_after doc and code disagreed about the default
2) new GUCs were missing from postgresql.conf.sample
3) Outdated source-code comment about bgwriter_flush_after's default
4) Sub-optimal categories assigned to new GUCs
5) Docs suggested backend_flush_after is PGC_SIGHUP, but it's PGC_USERSET.
6) Spell out int as integer in the docs, as done elsewhere
Reported-By: Magnus Hagander, Fujii Masao
Discussion: CAHGQGwETyTG5VYQQ5C_srwxWX7RXvFcD3dKROhvAWWhoSBdmZw@mail.gmail.com
---
doc/src/sgml/config.sgml | 10 ++--
src/backend/utils/misc/guc.c | 50 +++++++++----------
src/backend/utils/misc/postgresql.conf.sample | 6 +++
3 files changed, 35 insertions(+), 31 deletions(-)
diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml
index f9ba1487822..909b3e23c52 100644
--- a/doc/src/sgml/config.sgml
+++ b/doc/src/sgml/config.sgml
@@ -1884,7 +1884,7 @@ include_dir 'conf.d'
</varlistentry>
<varlistentry id="guc-bgwriter-flush-after" xreflabel="bgwriter_flush_after">
- <term><varname>bgwriter_flush_after</varname> (<type>int</type>)
+ <term><varname>bgwriter_flush_after</varname> (<type>integer</type>)
<indexterm>
<primary><varname>bgwriter_flush_after</> configuration parameter</primary>
</indexterm>
@@ -2014,7 +2014,7 @@ include_dir 'conf.d'
</varlistentry>
<varlistentry id="guc-backend-flush-after" xreflabel="backend_flush_after">
- <term><varname>backend_flush_after</varname> (<type>int</type>)
+ <term><varname>backend_flush_after</varname> (<type>integer</type>)
<indexterm>
<primary><varname>backend_flush_after</> configuration parameter</primary>
</indexterm>
@@ -2036,8 +2036,6 @@ include_dir 'conf.d'
and <literal>2MB</literal>. The default is <literal>128Kb</> on
Linux, <literal>0</> elsewhere. (Non-default values of
<symbol>BLCKSZ</symbol> change the default and maximum.)
- This parameter can only be set in the <filename>postgresql.conf</>
- file or on the server command line.
</para>
</listitem>
</varlistentry>
@@ -2607,7 +2605,7 @@ include_dir 'conf.d'
</varlistentry>
<varlistentry id="guc-checkpoint-flush-after" xreflabel="checkpoint_flush_after">
- <term><varname>checkpoint_flush_after</varname> (<type>int</type>)
+ <term><varname>checkpoint_flush_after</varname> (<type>integer</type>)
<indexterm>
<primary><varname>checkpoint_flush_after</> configuration parameter</primary>
</indexterm>
@@ -2626,7 +2624,7 @@ include_dir 'conf.d'
than the OS's page cache, where performance might degrade. This
setting may have no effect on some platforms. The valid range is
between <literal>0</literal>, which disables controlled writeback,
- and <literal>2MB</literal>. The default is <literal>128Kb</> on
+ and <literal>2MB</literal>. The default is <literal>256Kb</> on
Linux, <literal>0</> elsewhere. (Non-default values of
<symbol>BLCKSZ</symbol> change the default and maximum.)
This parameter can only be set in the <filename>postgresql.conf</>
diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c
index fb091bc4a0b..60856dda198 100644
--- a/src/backend/utils/misc/guc.c
+++ b/src/backend/utils/misc/guc.c
@@ -2273,6 +2273,18 @@ static struct config_int ConfigureNamesInt[] =
NULL, NULL, NULL
},
+ {
+ {"checkpoint_flush_after", PGC_SIGHUP, WAL_CHECKPOINTS,
+ gettext_noop("Number of pages after which previously performed writes are flushed to disk."),
+ NULL,
+ GUC_UNIT_BLOCKS
+ },
+ &checkpoint_flush_after,
+ /* see bufmgr.h: OS dependent default */
+ DEFAULT_CHECKPOINT_FLUSH_AFTER, 0, WRITEBACK_MAX_PENDING_FLUSHES,
+ NULL, NULL, NULL
+ },
+
{
{"wal_buffers", PGC_POSTMASTER, WAL_SETTINGS,
gettext_noop("Sets the number of disk-page buffers in shared memory for WAL."),
@@ -2419,6 +2431,18 @@ static struct config_int ConfigureNamesInt[] =
NULL, NULL, NULL
},
+ {
+ {"bgwriter_flush_after", PGC_SIGHUP, RESOURCES_BGWRITER,
+ gettext_noop("Number of pages after which previously performed writes are flushed to disk."),
+ NULL,
+ GUC_UNIT_BLOCKS
+ },
+ &bgwriter_flush_after,
+ /* see bufmgr.h: OS dependent default */
+ DEFAULT_BGWRITER_FLUSH_AFTER, 0, WRITEBACK_MAX_PENDING_FLUSHES,
+ NULL, NULL, NULL
+ },
+
{
{"effective_io_concurrency",
PGC_USERSET,
@@ -2436,19 +2460,7 @@ static struct config_int ConfigureNamesInt[] =
},
{
- {"checkpoint_flush_after", PGC_SIGHUP, RESOURCES_ASYNCHRONOUS,
- gettext_noop("Number of pages after which previously performed writes are flushed to disk."),
- NULL,
- GUC_UNIT_BLOCKS
- },
- &checkpoint_flush_after,
- /* see bufmgr.h: OS dependent default */
- DEFAULT_CHECKPOINT_FLUSH_AFTER, 0, WRITEBACK_MAX_PENDING_FLUSHES,
- NULL, NULL, NULL
- },
-
- {
- {"backend_flush_after", PGC_USERSET, WAL_CHECKPOINTS,
+ {"backend_flush_after", PGC_USERSET, RESOURCES_ASYNCHRONOUS,
gettext_noop("Number of pages after which previously performed writes are flushed to disk."),
NULL,
GUC_UNIT_BLOCKS
@@ -2459,18 +2471,6 @@ static struct config_int ConfigureNamesInt[] =
NULL, NULL, NULL
},
- {
- {"bgwriter_flush_after", PGC_SIGHUP, WAL_CHECKPOINTS,
- gettext_noop("Number of pages after which previously performed writes are flushed to disk."),
- NULL,
- GUC_UNIT_BLOCKS
- },
- &bgwriter_flush_after,
- /* see bufmgr.h: 16 on Linux, 0 otherwise */
- DEFAULT_BGWRITER_FLUSH_AFTER, 0, WRITEBACK_MAX_PENDING_FLUSHES,
- NULL, NULL, NULL
- },
-
{
{"max_worker_processes",
PGC_POSTMASTER,
diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample
index d4dd285ef0a..14b537ffb17 100644
--- a/src/backend/utils/misc/postgresql.conf.sample
+++ b/src/backend/utils/misc/postgresql.conf.sample
@@ -160,6 +160,8 @@
#bgwriter_delay = 200ms # 10-10000ms between rounds
#bgwriter_lru_maxpages = 100 # 0-1000 max buffers written/round
#bgwriter_lru_multiplier = 2.0 # 0-10.0 multiplier on buffers scanned/round
+#bgwriter_flush_after = 0 # 0 disables,
+ # default is 512kb on linux, 0 otherwise
# - Asynchronous Behavior -
@@ -168,6 +170,8 @@
#max_parallel_degree = 0 # max number of worker processes per node
#old_snapshot_threshold = -1 # 1min-60d; -1 disables; 0 is immediate
# (change requires restart)
+#backend_flush_after = 0 # 0 disables,
+ # default is 128kb on linux, 0 otherwise
#------------------------------------------------------------------------------
@@ -206,6 +210,8 @@
#max_wal_size = 1GB
#min_wal_size = 80MB
#checkpoint_completion_target = 0.5 # checkpoint target duration, 0.0 - 1.0
+#checkpoint_flush_after = 0 # 0 disables,
+ # default is 256kb on linux, 0 otherwise
#checkpoint_warning = 30s # 0 disables
# - Archiving -
--
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