diff options
Diffstat (limited to 'doc/src/sgml/ref/create_index.sgml')
| -rw-r--r-- | doc/src/sgml/ref/create_index.sgml | 17 |
1 files changed, 7 insertions, 10 deletions
diff --git a/doc/src/sgml/ref/create_index.sgml b/doc/src/sgml/ref/create_index.sgml index be0ca63f2c5..d89a553a86f 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 1.56 2006/08/25 04:06:45 tgl Exp $ +$PostgreSQL: pgsql/doc/src/sgml/ref/create_index.sgml,v 1.57 2006/09/13 23:42:26 tgl Exp $ PostgreSQL documentation --> @@ -264,22 +264,19 @@ CREATE [ UNIQUE ] INDEX [ CONCURRENTLY ] <replaceable class="parameter">name</re </indexterm> <para> - Creating an index for a large table can be a long operation. In large data - warehousing applications it can easily take hours or even days to build - indexes. It's important to understand the impact creating indexes has on a - system. - </para> - - <para> + Creating an index can interfere with regular operation of a database. Normally <productname>PostgreSQL</> locks the table to be indexed against writes and performs the entire index build with a single scan of the table. Other transactions can still read the table, but if they try to insert, update, or delete rows in the table they will block until the - index build is finished. + index build is finished. This could have a severe effect if the system is + a live production database. Large tables can take many hours to be + indexed, and even for smaller tables, an index build can lock out writers + for periods that are unacceptably long for a production system. </para> <para> - <productname>PostgreSQL</> also supports building indexes without locking + <productname>PostgreSQL</> supports building indexes without locking out writes. This method is invoked by specifying the <literal>CONCURRENTLY</> option of <command>CREATE INDEX</>. When this option is used, |