From cee63eab8dd52b5341ecde40b684d400eb09bf0b Mon Sep 17 00:00:00 2001
From: Bruce Momjian <bruce@momjian.us>
Date: Thu, 18 Dec 2008 17:03:09 +0000
Subject: [PATCH] Update documentation table describing how shared memory is
used by various facilities.
---
doc/src/sgml/runtime.sgml | 44 +++++++++++++++++----------------------
1 file changed, 19 insertions(+), 25 deletions(-)
diff --git a/doc/src/sgml/runtime.sgml b/doc/src/sgml/runtime.sgml
index c48ffa57afa..13731a318cd 100644
--- a/doc/src/sgml/runtime.sgml
+++ b/doc/src/sgml/runtime.sgml
@@ -1,4 +1,4 @@
-<!-- $PostgreSQL: pgsql/doc/src/sgml/runtime.sgml,v 1.423 2008/12/16 19:30:43 alvherre Exp $ -->
+<!-- $PostgreSQL: pgsql/doc/src/sgml/runtime.sgml,v 1.424 2008/12/18 17:03:09 momjian Exp $ -->
<chapter Id="runtime">
<title>Operating System Environment</title>
@@ -1080,41 +1080,45 @@ set semsys:seminfo_semmsl=32
<table id="shared-memory-parameters">
- <title>Configuration parameters affecting
- <productname>PostgreSQL</productname>'s shared memory usage</>
+ <title><productname>PostgreSQL</productname> shared memory usage</>
<tgroup cols="2">
<thead>
<row>
- <entry>Name</>
- <entry>Approximate multiplier (bytes per increment) as of 8.3</>
+ <entry>Usage</>
+ <entry>Approximate shared memory bytes required (as of 8.3)</>
</row>
</thead>
<tbody>
<row>
- <entry><xref linkend="guc-max-connections"></>
- <entry>1800 + 270 * <xref linkend="guc-max-locks-per-transaction"></entry>
+ <entry>Connections</>
+ <entry>(1800 + 270 * <xref
+ linkend="guc-max-locks-per-transaction">) * <xref
+ linkend="guc-max-connections"></entry>
</row>
<row>
- <entry><xref linkend="guc-autovacuum-max-workers"></>
- <entry>1800 + 270 * <xref linkend="guc-max-locks-per-transaction"></entry>
+ <entry>Autovacuum workers</>
+ <entry>(1800 + 270 * <xref
+ linkend="guc-max-locks-per-transaction">) * <xref
+ linkend="guc-autovacuum-max-workers"></entry>
</row>
<row>
- <entry><xref linkend="guc-max-prepared-transactions"></>
- <entry>770 + 270 * <xref linkend="guc-max-locks-per-transaction"></entry>
+ <entry>Prepared transactions</>
+ <entry>(770 + 270 * <xref
+ linkend="guc-max-locks-per-transaction">) * <xref linkend="guc-max-prepared-transactions"></entry>
</row>
<row>
- <entry><xref linkend="guc-shared-buffers"></>
- <entry>8400 (assuming 8 kB <symbol>BLCKSZ</>)</entry>
+ <entry>Shared disk buffers</>
+ <entry>(<xref linkend="guc-block-size"> + 208) * <xref linkend="guc-shared-buffers"></entry>
</row>
<row>
- <entry><xref linkend="guc-wal-buffers"></>
- <entry>8200 (assuming 8 kB <symbol>XLOG_BLCKSZ</>)</entry>
+ <entry>WAL buffers</>
+ <entry>(<xref linkend="guc-wal-block-size"> + 8) * <xref linkend="guc-wal-buffers"></entry>
</row>
<row>
@@ -1125,18 +1129,8 @@ set semsys:seminfo_semmsl=32
</tgroup>
</table>
- <note>
- <para>
- The multipliers for <varname>shared_buffers</> and
- <varname>wal_buffers</> should be the number of buffers, not the
- amount in bytes. To find out the number of shared or wal buffers, divide
- the amount in bytes by <xref linkend="guc-block-size"> and
- <xref linkend="guc-wal-block-size">, respectively.
- </para>
- </note>
</sect2>
-
<sect2>
<title>Resource Limits</title>
--
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