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Instead of having a configure-time DEFAULT_ATTSTATTARGET, store -1 in

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attstattarget to indicate 'use the default'.  The default is now a GUC
variable default_statistics_target, and so may be changed on the fly.  Along
the way we gain the ability to have pg_dump dump the per-column statistics
target when it's not the default.  Patch by Neil Conway, with some kibitzing
from Tom Lane.
This commit is contained in:
Tom Lane
2002-07-31 17:19:54 +00:00
parent 8be3cfbbd5
commit ce7565ab91
18 changed files with 125 additions and 60 deletions
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4
doc/src/sgml/ref/alter_table.sgml
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@@ -1,5 +1,5 @@
<!--
$Header: /cvsroot/pgsql/doc/src/sgml/ref/alter_table.sgml,v 1.46 2002/07/12 18:43:12 tgl Exp $
$Header: /cvsroot/pgsql/doc/src/sgml/ref/alter_table.sgml,v 1.47 2002/07/31 17:19:50 tgl Exp $
PostgreSQL documentation
-->
@@ -218,6 +218,8 @@ ALTER TABLE <replaceable class="PARAMETER">table</replaceable>
This form
sets the per-column statistics-gathering target for subsequent
<xref linkend="sql-analyze" endterm="sql-analyze-title"> operations.
The target can be set in the range 0 to 1000; alternatively, set it
to -1 to revert to using the system default statistics target.
</para>
</listitem>
</varlistentry>

10
doc/src/sgml/ref/analyze.sgml
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@@ -1,5 +1,5 @@
<!--
$Header: /cvsroot/pgsql/doc/src/sgml/ref/analyze.sgml,v 1.8 2002/04/23 02:07:15 tgl Exp $
$Header: /cvsroot/pgsql/doc/src/sgml/ref/analyze.sgml,v 1.9 2002/07/31 17:19:51 tgl Exp $
PostgreSQL documentation
-->
@@ -157,7 +157,9 @@ ANALYZE [ VERBOSE ] [ <replaceable class="PARAMETER">table</replaceable> [ (<rep
</para>
<para>
The extent of analysis can be controlled by adjusting the per-column
The extent of analysis can be controlled by adjusting the
<literal>default_statistics_target</> parameter variable, or on a
column-by-column basis by setting the per-column
statistics target with <command>ALTER TABLE ALTER COLUMN SET
STATISTICS</command> (see
<xref linkend="sql-altertable" endterm="sql-altertable-title">). The
@@ -165,8 +167,8 @@ ANALYZE [ VERBOSE ] [ <replaceable class="PARAMETER">table</replaceable> [ (<rep
list and the maximum number of bins in the histogram. The default
target value is 10, but this can be adjusted up or down to trade off
accuracy of planner estimates against the time taken for
<command>ANALYZE</command> and the
amount of space occupied in <literal>pg_statistic</literal>.
<command>ANALYZE</command> and the amount of space occupied
in <literal>pg_statistic</literal>.
In particular, setting the statistics target to zero disables collection of
statistics for that column. It may be useful to do that for columns that
are never used as part of the WHERE, GROUP BY, or ORDER BY clauses of