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Allow CREATE INDEX CONCURRENTLY to disregard transactions in other

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databases, per gripe from hubert depesz lubaczewski.  Patch from
Simon Riggs.
This commit is contained in:
Tom Lane
2007-09-07 00:58:57 +00:00
parent f8942f4a15
commit cd1aae5864
4 changed files with 33 additions and 24 deletions
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7
doc/src/sgml/ref/create_index.sgml
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@ -1,5 +1,5 @@
<!--
$PostgreSQL: pgsql/doc/src/sgml/ref/create_index.sgml,v 1.63 2007/06/03 17:05:53 tgl Exp $
$PostgreSQL: pgsql/doc/src/sgml/ref/create_index.sgml,v 1.64 2007/09/07 00:58:56 tgl Exp $
PostgreSQL documentation
-->
@ -308,7 +308,7 @@ CREATE [ UNIQUE ] INDEX [ CONCURRENTLY ] <replaceable class="parameter">name</re
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. This could have a severe effect if the system is
a live production database. Large tables can take many hours to be
a live production database. Very 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>
@ -319,7 +319,8 @@ CREATE [ UNIQUE ] INDEX [ CONCURRENTLY ] <replaceable class="parameter">name</re
<literal>CONCURRENTLY</> option of <command>CREATE INDEX</>.
When this option is used,
<productname>PostgreSQL</> must perform two scans of the table, and in
addition it must wait for all existing transactions to terminate. Thus
addition it must wait for all existing transactions that could potentially
use the index to terminate. Thus
this method requires more total work than a standard index build and takes
significantly longer to complete. However, since it allows normal
operations to continue while the index is built, this method is useful for