diff options
Diffstat (limited to 'doc/src/sgml/ref/create_index.sgml')
| -rw-r--r-- | doc/src/sgml/ref/create_index.sgml | 12 |
1 files changed, 6 insertions, 6 deletions
diff --git a/doc/src/sgml/ref/create_index.sgml b/doc/src/sgml/ref/create_index.sgml index d64901d2e9..db873c7207 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 1.59 2007/01/09 02:14:10 tgl Exp $ +$PostgreSQL: pgsql/doc/src/sgml/ref/create_index.sgml,v 1.60 2007/01/31 23:26:03 momjian Exp $ PostgreSQL documentation --> @@ -75,7 +75,7 @@ CREATE [ UNIQUE ] INDEX [ CONCURRENTLY ] <replaceable class="parameter">name</re </para> <para> - The expression used in the <literal>WHERE</literal> clause may refer + The expression used in the <literal>WHERE</literal> clause can refer only to columns of the underlying table, but it can use all columns, not just the ones being indexed. Presently, subqueries and aggregate expressions are also forbidden in <literal>WHERE</literal>. @@ -172,7 +172,7 @@ CREATE [ UNIQUE ] INDEX [ CONCURRENTLY ] <replaceable class="parameter">name</re <para> An expression based on one or more columns of the table. The expression usually must be written with surrounding parentheses, - as shown in the syntax. However, the parentheses may be omitted + as shown in the syntax. However, the parentheses can be omitted if the expression has the form of a function call. </para> </listitem> @@ -324,14 +324,14 @@ CREATE [ UNIQUE ] INDEX [ CONCURRENTLY ] <replaceable class="parameter">name</re significantly longer to complete. However, since it allows normal operations to continue while the index is built, this method is useful for adding new indexes in a production environment. Of course, the extra CPU - and I/O load imposed by the index creation may slow other operations. + and I/O load imposed by the index creation might slow other operations. </para> <para> If a problem arises during the second scan of the table, such as a uniqueness violation in a unique index, the <command>CREATE INDEX</> command will fail but leave behind an <quote>invalid</> index. This index - will be ignored for querying purposes because it may be incomplete; + will be ignored for querying purposes because it might be incomplete; however it will still consume update overhead. The recommended recovery method in such cases is to drop the index and try again to perform <command>CREATE INDEX CONCURRENTLY</>. (Another possibility is to rebuild @@ -378,7 +378,7 @@ CREATE [ UNIQUE ] INDEX [ CONCURRENTLY ] <replaceable class="parameter">name</re <para> Currently, only the B-tree and GiST index methods support - multicolumn indexes. Up to 32 fields may be specified by default. + multicolumn indexes. Up to 32 fields can be specified by default. (This limit can be altered when building <productname>PostgreSQL</productname>.) Only B-tree currently supports unique indexes. |