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Rename SortMem and VacuumMem to work_mem and maintenance_work_mem.

Browse Source 
Make btree index creation and initial validation of foreign-key constraints
use maintenance_work_mem rather than work_mem as their memory limit.
Add some code to guc.c to allow these variables to be referenced by their
old names in SHOW and SET commands, for backwards compatibility.
This commit is contained in:
Tom Lane
2004-02-03 17:34:04 +00:00
parent 39d715bee6
commit 391c3811a2
34 changed files with 269 additions and 188 deletions
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6
doc/src/sgml/backup.sgml
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@ -1,5 +1,5 @@
<!--
$PostgreSQL: pgsql/doc/src/sgml/backup.sgml,v 2.34 2004/01/19 20:12:30 tgl Exp $
$PostgreSQL: pgsql/doc/src/sgml/backup.sgml,v 2.35 2004/02/03 17:34:02 tgl Exp $
-->
<chapter id="backup">
<title>Backup and Restore</title>
@ -156,8 +156,8 @@ pg_dump -h <replaceable>host1</> <replaceable>dbname</> | psql -h <replaceable>h
<tip>
<para>
Restore performance can be improved by increasing the
configuration parameter <varname>sort_mem</varname> (see <xref
linkend="runtime-config-resource-memory">).
configuration parameter <varname>maintenance_work_mem</varname>
(see <xref linkend="runtime-config-resource-memory">).
</para>
</tip>
</sect2>

4
doc/src/sgml/installation.sgml
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@ -1,4 +1,4 @@
<!-- $PostgreSQL: pgsql/doc/src/sgml/installation.sgml,v 1.193 2004/01/19 21:20:06 tgl Exp $ -->
<!-- $PostgreSQL: pgsql/doc/src/sgml/installation.sgml,v 1.194 2004/02/03 17:34:02 tgl Exp $ -->
<chapter id="installation">
<title><![%standalone-include[<productname>PostgreSQL</>]]>
@ -1399,7 +1399,7 @@ kill `cat /usr/local/pgsql/data/postmaster.pid`
not designed for optimum performance. To achieve optimum
performance, several server parameters must be adjusted, the two
most common being <varname>shared_buffers</varname> and
<varname> sort_mem</varname> mentioned in the documentation.
<varname>work_mem</varname>.
Other parameters mentioned in the documentation also affect
performance.
</para>

14
doc/src/sgml/perform.sgml
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@ -1,5 +1,5 @@
<!--
$PostgreSQL: pgsql/doc/src/sgml/perform.sgml,v 1.40 2004/01/11 05:46:58 neilc Exp $
$PostgreSQL: pgsql/doc/src/sgml/perform.sgml,v 1.41 2004/02/03 17:34:02 tgl Exp $
-->
<chapter id="performance-tips">
@ -684,16 +684,18 @@ SELECT * FROM x, y, a, b, c WHERE something AND somethingelse;
</para>
</sect2>
<sect2 id="populate-sort-mem">
<title>Increase <varname>sort_mem</varname></title>
<sect2 id="populate-work-mem">
<title>Increase <varname>maintenance_work_mem</varname></title>
<para>
Temporarily increasing the <varname>sort_mem</varname>
Temporarily increasing the <varname>maintenance_work_mem</varname>
configuration variable when restoring large amounts of data can
lead to improved performance. This is because when a B-tree index
is created from scratch, the existing content of the table needs
to be sorted. Allowing the merge sort to use more buffer pages
means that fewer merge passes will be required.
to be sorted. Allowing the merge sort to use more memory
means that fewer merge passes will be required. A larger setting for
<varname>maintenance_work_mem</varname> may also speed up validation
of foreign-key constraints.
</para>
</sect2>

4
doc/src/sgml/plpgsql.sgml
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@ -1,5 +1,5 @@
<!--
$PostgreSQL: pgsql/doc/src/sgml/plpgsql.sgml,v 1.34 2004/01/24 22:05:08 tgl Exp $
$PostgreSQL: pgsql/doc/src/sgml/plpgsql.sgml,v 1.35 2004/02/03 17:34:02 tgl Exp $
-->
<chapter id="plpgsql">
@ -1354,7 +1354,7 @@ SELECT * FROM some_func();
allow users to define set-returning functions
that do not have this limitation. Currently, the point at
which data begins being written to disk is controlled by the
<varname>sort_mem</> configuration variable. Administrators
<varname>work_mem</> configuration variable. Administrators
who have sufficient memory to store larger result sets in
memory should consider increasing this parameter.
</para>

17
doc/src/sgml/ref/postgres-ref.sgml
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@ -1,5 +1,5 @@
<!--
$PostgreSQL: pgsql/doc/src/sgml/ref/postgres-ref.sgml,v 1.42 2003/11/29 19:51:39 pgsql Exp $
$PostgreSQL: pgsql/doc/src/sgml/ref/postgres-ref.sgml,v 1.43 2004/02/03 17:34:02 tgl Exp $
PostgreSQL documentation
-->
@ -41,7 +41,7 @@ PostgreSQL documentation
<arg>-s</arg>
<arg>-t<group choice="plain"><arg>pa</arg><arg>pl</arg><arg>ex</arg></group></arg>
</group>
<arg>-S <replaceable>sort-mem</replaceable></arg>
<arg>-S <replaceable>work-mem</replaceable></arg>
<arg>-W <replaceable>seconds</replaceable></arg>
<arg>--<replaceable>name</replaceable>=<replaceable>value</replaceable></arg>
<arg choice="plain"><replaceable>database</replaceable></arg>
@ -64,7 +64,7 @@ PostgreSQL documentation
<arg>-s</arg>
<arg>-t<group choice="plain"><arg>pa</arg><arg>pl</arg><arg>ex</arg></group></arg>
</group>
<arg>-S <replaceable>sort-mem</replaceable></arg>
<arg>-S <replaceable>work-mem</replaceable></arg>
<arg>-v <replaceable>protocol</replaceable></arg>
<arg>-W <replaceable>seconds</replaceable></arg>
<arg>--<replaceable>name</replaceable>=<replaceable>value</replaceable></arg>
@ -197,16 +197,13 @@ PostgreSQL documentation
</varlistentry>
<varlistentry>
<term><option>-S</option> <replaceable class="parameter">sort-mem</replaceable></term>
<term><option>-S</option> <replaceable class="parameter">work-mem</replaceable></term>
<listitem>
<para>
Specifies the amount of memory to be used by internal sorts and hashes
before resorting to temporary disk files. The value is specified in
kilobytes, and defaults to 1024. Note that for a complex query,
several sorts and/or hashes might be running in parallel, and each one
will be allowed to use as much as
<replaceable class="parameter">sort-mem</replaceable> kilobytes
before it starts to put data into temporary files.
before resorting to temporary disk files. See the description of the
<varname>work_mem</> configuration parameter in <xref
linkend="runtime-config-resource-memory">.
</para>
</listitem>
</varlistentry>

8
doc/src/sgml/ref/postmaster.sgml
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@ -1,5 +1,5 @@
<!--
$PostgreSQL: pgsql/doc/src/sgml/ref/postmaster.sgml,v 1.44 2003/12/14 00:15:03 neilc Exp $
$PostgreSQL: pgsql/doc/src/sgml/ref/postmaster.sgml,v 1.45 2004/02/03 17:34:02 tgl Exp $
PostgreSQL documentation
-->
@ -541,10 +541,10 @@ PostgreSQL documentation
<para>
Named run-time parameters can be set in either of these styles:
<screen>
<prompt>$</prompt> <userinput>postmaster -c sort_mem=1234</userinput>
<prompt>$</prompt> <userinput>postmaster --sort-mem=1234</userinput>
<prompt>$</prompt> <userinput>postmaster -c work_mem=1234</userinput>
<prompt>$</prompt> <userinput>postmaster --work-mem=1234</userinput>
</screen>
Either form overrides whatever setting might exist for <varname>sort_mem</>
Either form overrides whatever setting might exist for <varname>work_mem</>
in <filename>postgresql.conf</>. Notice that underscores in parameter
names can be written as either underscore or dash on the command line.
</para>

84
doc/src/sgml/runtime.sgml
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@ -1,5 +1,5 @@
<!--
$PostgreSQL: pgsql/doc/src/sgml/runtime.sgml,v 1.235 2004/01/27 16:51:43 neilc Exp $
$PostgreSQL: pgsql/doc/src/sgml/runtime.sgml,v 1.236 2004/02/03 17:34:02 tgl Exp $
-->
<Chapter Id="runtime">
@ -850,37 +850,41 @@ SET ENABLE_SEQSCAN TO OFF;
</varlistentry>
<varlistentry>
<term><varname>sort_mem</varname> (<type>integer</type>)</term>
<term><varname>work_mem</varname> (<type>integer</type>)</term>
<listitem>
<para>
Specifies the amount of memory to be used by internal sort operations and
hash tables before switching to temporary disk files. The value is
Specifies the amount of memory to be used by internal sort operations
and hash tables before switching to temporary disk files. The value is
specified in kilobytes, and defaults to 1024 kilobytes (1 MB).
Note that for a complex query, several sort or hash operations might be
running in parallel; each one will be allowed to use as much memory
as this value specifies before it starts to put data into temporary
files. Also, several running sessions could be doing
sort operations simultaneously. So the total memory used could be many
times the value of <varname>sort_mem</varname>. Sort operations are used
by <literal>ORDER BY</>, merge joins, and <command>CREATE INDEX</>.
files. Also, several running sessions could be doing such operations
concurrently. So the total memory used could be many
times the value of <varname>work_mem</varname>; it is necessary to
keep this fact in mind when choosing the value. Sort operations are
used for <literal>ORDER BY</>, <literal>DISTINCT</>, and
merge joins.
Hash tables are used in hash joins, hash-based aggregation, and
hash-based processing of <literal>IN</> subqueries. Because
<command>CREATE INDEX</> is used when restoring a database,
increasing <varname>sort_mem</varname> before doing a large
restore operation can improve performance.
hash-based processing of <literal>IN</> subqueries.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><varname>vacuum_mem</varname> (<type>integer</type>)</term>
<term><varname>maintenance_work_mem</varname> (<type>integer</type>)</term>
<listitem>
<para>
Specifies the maximum amount of memory to be used by
<command>VACUUM</command> to keep track of to-be-reclaimed
rows. The value is specified in kilobytes, and defaults to
8192 kB. Larger settings may improve the speed of
vacuuming large tables that have many deleted rows.
Specifies the maximum amount of memory to be used in maintenance
operations, such as <command>VACUUM</command>, <command>CREATE
INDEX</>, and <command>ALTER TABLE ADD FOREIGN KEY</>.
The value is specified in kilobytes, and defaults to 16384 kilobytes
(16 MB). Since only one of these operations can be executed at
a time by a database session, and an installation normally doesn't
have very many of them happening concurrently, it's safe to set this
value significantly larger than <varname>work_mem</varname>. Larger
settings may improve performance for vacuuming and for restoring
database dumps.
</para>
</listitem>
</varlistentry>
@ -1412,25 +1416,25 @@ SET ENABLE_SEQSCAN TO OFF;
<para>
Various tuning parameters for the genetic query optimization
algorithm. The recommended one to modify is
<varname>geqo_effort</varname>, which can range from 1 to 10 with
a default of 5. Larger values increase the time spent in planning
but make it more likely that a good plan will be found.
<varname>geqo_effort</varname> doesn't actually do anything directly,
it is just used to compute the default values for the other
parameters. If you prefer, you can set the other parameters by hand
instead.
The pool size is the number of individuals in the genetic population.
It must be at least two, and useful values are typically 100 to 1000.
If it is set to zero (the default setting) then a suitable default
is chosen based on <varname>geqo_effort</varname> and the number of
tables in the query.
Generations specifies the number of iterations of the algorithm.
It must be at least one, and useful values are in the same range
as the pool size.
If it is set to zero (the default setting) then a suitable default
is chosen based on the pool size.
The run time of the algorithm is roughly proportional to the sum of
pool size and generations.
<varname>geqo_effort</varname>, which can range from 1 to 10 with
a default of 5. Larger values increase the time spent in planning
but make it more likely that a good plan will be found.
<varname>geqo_effort</varname> doesn't actually do anything directly,
it is just used to compute the default values for the other
parameters. If you prefer, you can set the other parameters by hand
instead.
The pool size is the number of individuals in the genetic population.
It must be at least two, and useful values are typically 100 to 1000.
If it is set to zero (the default setting) then a suitable default
is chosen based on <varname>geqo_effort</varname> and the number of
tables in the query.
Generations specifies the number of iterations of the algorithm.
It must be at least one, and useful values are in the same range
as the pool size.
If it is set to zero (the default setting) then a suitable default
is chosen based on the pool size.
The run time of the algorithm is roughly proportional to the sum of
pool size and generations.
The selection bias is the selective pressure within the
population. Values can be from 1.50 to 2.00; the latter is the
default.
@ -2840,7 +2844,7 @@ $ <userinput>postmaster -o '-S 1024 -s'</userinput>
<row>
<entry><option>-S <replaceable>x</replaceable></option><footnoteref linkend="fn.runtime-config-short">
</entry>
<entry><literal>sort_mem = <replaceable>x</replaceable></></entry>
<entry><literal>work_mem = <replaceable>x</replaceable></></entry>
</row>
<row>
@ -3230,7 +3234,7 @@ kernel.shmmax = 134217728
<para>
In OS X 10.2 and earlier, edit the file
<filename>/System/Library/StartupItems/SystemTuning/SystemTuning</>
and change the values in the following commands:
and change the values in the following commands:
<programlisting>
sysctl -w kern.sysv.shmmax
sysctl -w kern.sysv.shmmin
@ -3239,7 +3243,7 @@ sysctl -w kern.sysv.shmseg
sysctl -w kern.sysv.shmall
</programlisting>
In OS X 10.3, these commands have been moved to <filename>/etc/rc</>
and must be edited there.
and must be edited there.
</para>
</listitem>
</varlistentry>