diff options
| -rw-r--r-- | doc/src/sgml/ref/create_index.sgml | 21 |
1 files changed, 19 insertions, 2 deletions
diff --git a/doc/src/sgml/ref/create_index.sgml b/doc/src/sgml/ref/create_index.sgml index 7686700d78d..32b7bbebd99 100644 --- a/doc/src/sgml/ref/create_index.sgml +++ b/doc/src/sgml/ref/create_index.sgml @@ -1,5 +1,5 @@ <!-- -$PostgreSQL: pgsql/doc/src/sgml/ref/create_index.sgml,v 1.66 2007/11/26 21:36:33 petere Exp $ +$PostgreSQL: pgsql/doc/src/sgml/ref/create_index.sgml,v 1.67 2008/03/16 23:57:51 tgl Exp $ PostgreSQL documentation --> @@ -32,7 +32,7 @@ CREATE [ UNIQUE ] INDEX [ CONCURRENTLY ] <replaceable class="parameter">name</re <title>Description</title> <para> - <command>CREATE INDEX</command> constructs an index <replaceable + <command>CREATE INDEX</command> constructs an index named <replaceable class="parameter">name</replaceable> on the specified table. Indexes are primarily used to enhance database performance (though inappropriate use can result in slower performance). @@ -434,6 +434,23 @@ Indexes: </para> <para> + For most index methods, the speed of creating an index is + dependent on the setting of <xref linkend="guc-maintenance-work-mem">. + Larger values will reduce the time needed for index creation, so long + as you don't make it larger than the amount of memory really available, + which would drive the machine into swapping. For hash indexes, the + value of <xref linkend="guc-effective-cache-size"> is also relevant to + index creation time: <productname>PostgreSQL</productname> will use one + of two different hash index creation methods depending on whether the + estimated index size is more or less than <varname>effective_cache_size</>. + For best results, make sure that this parameter is also set to something + reflective of available memory, and be careful that the sum of + <varname>maintenance_work_mem</> and <varname>effective_cache_size</> is + less than the machine's RAM less whatever space is needed by other + programs. + </para> + + <para> Use <xref linkend="sql-dropindex" endterm="sql-dropindex-title"> to remove an index. </para> |