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 @@ @@ -32,7 +32,7 @@ CREATE [ UNIQUE ] INDEX [ CONCURRENTLY ] nameDescription - CREATE INDEX constructs an index CREATE INDEX constructs an index named name on the specified table. Indexes are primarily used to enhance database performance (though inappropriate use can result in slower performance). @@ -433,6 +433,23 @@ Indexes: sort high, in queries that depend on indexes to avoid sorting steps. + + For most index methods, the speed of creating an index is + dependent on the setting of . + 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 is also relevant to + index creation time: PostgreSQL will use one + of two different hash index creation methods depending on whether the + estimated index size is more or less than 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 + maintenance_work_mem and effective_cache_size is + less than the machine's RAM less whatever space is needed by other + programs. + + Use to remove an index.