diff options
Diffstat (limited to 'doc/src')
| -rw-r--r-- | doc/src/sgml/config.sgml | 4 | ||||
| -rw-r--r-- | doc/src/sgml/perform.sgml | 4 | ||||
| -rw-r--r-- | doc/src/sgml/ref/alter_table.sgml | 4 | ||||
| -rw-r--r-- | doc/src/sgml/ref/analyze.sgml | 12 |
4 files changed, 12 insertions, 12 deletions
diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index cf99ba2c85f..86ccac9448c 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -1,4 +1,4 @@ -<!-- $PostgreSQL: pgsql/doc/src/sgml/config.sgml,v 1.199 2008/12/08 15:11:39 mha Exp $ --> +<!-- $PostgreSQL: pgsql/doc/src/sgml/config.sgml,v 1.200 2008/12/13 19:13:43 tgl Exp $ --> <chapter Id="runtime-config"> <title>Server Configuration</title> @@ -2133,7 +2133,7 @@ archive_command = 'copy "%p" "C:\\server\\archivedir\\%f"' # Windows not had a column-specific target set via <command>ALTER TABLE SET STATISTICS</>. Larger values increase the time needed to do <command>ANALYZE</>, but might improve the quality of the - planner's estimates. The default is 10. For more information + planner's estimates. The default is 100. For more information on the use of statistics by the <productname>PostgreSQL</> query planner, refer to <xref linkend="planner-stats">. </para> diff --git a/doc/src/sgml/perform.sgml b/doc/src/sgml/perform.sgml index be5ec9f2c2e..aea529552c6 100644 --- a/doc/src/sgml/perform.sgml +++ b/doc/src/sgml/perform.sgml @@ -1,4 +1,4 @@ -<!-- $PostgreSQL: pgsql/doc/src/sgml/perform.sgml,v 1.68 2007/12/28 21:03:31 tgl Exp $ --> +<!-- $PostgreSQL: pgsql/doc/src/sgml/perform.sgml,v 1.69 2008/12/13 19:13:43 tgl Exp $ --> <chapter id="performance-tips"> <title>Performance Tips</title> @@ -562,7 +562,7 @@ SELECT attname, n_distinct, most_common_vals FROM pg_stats WHERE tablename = 'ro column-by-column basis using the <command>ALTER TABLE SET STATISTICS</> command, or globally by setting the <xref linkend="guc-default-statistics-target"> configuration variable. - The default limit is presently 10 entries. Raising the limit + The default limit is presently 100 entries. Raising the limit might allow more accurate planner estimates to be made, particularly for columns with irregular data distributions, at the price of consuming more space in <structname>pg_statistic</structname> and slightly more diff --git a/doc/src/sgml/ref/alter_table.sgml b/doc/src/sgml/ref/alter_table.sgml index 61cd403fcfd..b19c89f4211 100644 --- a/doc/src/sgml/ref/alter_table.sgml +++ b/doc/src/sgml/ref/alter_table.sgml @@ -1,5 +1,5 @@ <!-- -$PostgreSQL: pgsql/doc/src/sgml/ref/alter_table.sgml,v 1.101 2008/11/14 10:22:45 petere Exp $ +$PostgreSQL: pgsql/doc/src/sgml/ref/alter_table.sgml,v 1.102 2008/12/13 19:13:44 tgl Exp $ PostgreSQL documentation --> @@ -142,7 +142,7 @@ where <replaceable class="PARAMETER">action</replaceable> is one of: 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 + The target can be set in the range 0 to 10000; alternatively, set it to -1 to revert to using the system default statistics target (<xref linkend="guc-default-statistics-target">). For more information on the use of statistics by the diff --git a/doc/src/sgml/ref/analyze.sgml b/doc/src/sgml/ref/analyze.sgml index ad851405856..418082e6d93 100644 --- a/doc/src/sgml/ref/analyze.sgml +++ b/doc/src/sgml/ref/analyze.sgml @@ -1,5 +1,5 @@ <!-- -$PostgreSQL: pgsql/doc/src/sgml/ref/analyze.sgml,v 1.24 2008/11/14 10:22:45 petere Exp $ +$PostgreSQL: pgsql/doc/src/sgml/ref/analyze.sgml,v 1.25 2008/12/13 19:13:44 tgl Exp $ PostgreSQL documentation --> @@ -132,10 +132,10 @@ ANALYZE [ VERBOSE ] [ <replaceable class="PARAMETER">table</replaceable> [ ( <re will change slightly each time <command>ANALYZE</command> is run, even if the actual table contents did not change. This might result in small changes in the planner's estimated costs shown by - <xref linkend="sql-explain" endterm="sql-explain-title">. In rare situations, this - non-determinism will cause the query optimizer to choose a - different query plan between runs of <command>ANALYZE</command>. To - avoid this, raise the amount of statistics collected by + <xref linkend="sql-explain" endterm="sql-explain-title">. + In rare situations, this non-determinism will cause the planner's + choices of query plans to change after <command>ANALYZE</command> is run. + To avoid this, raise the amount of statistics collected by <command>ANALYZE</command>, as described below. </para> @@ -148,7 +148,7 @@ ANALYZE [ VERBOSE ] [ <replaceable class="PARAMETER">table</replaceable> [ ( <re endterm="sql-altertable-title">). The target value sets the maximum number of entries in the most-common-value 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 + is 100, 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>. In particular, setting the |