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CLUSTER cleanup

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This commit is contained in:
Bruce Momjian 1998-03-15 02:13:23 +00:00
parent 006fd9253f
commit 7eddadee87
1 changed files with 5 additions and 4 deletions
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src/man/cluster.l
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@ -1,6 +1,6 @@
.\" This is -*-nroff-*- .\" This is -*-nroff-*-
.\" XXX standard disclaimer belongs here.... .\" XXX standard disclaimer belongs here....
.\" $Header: /cvsroot/pgsql/src/man/Attic/cluster.l,v 1.6 1998/03/14 22:55:21 momjian Exp $ .\" $Header: /cvsroot/pgsql/src/man/Attic/cluster.l,v 1.7 1998/03/15 02:13:23 momjian Exp $
.TH CLUSTER SQL 01/23/93 PostgreSQL PostgreSQL .TH CLUSTER SQL 01/23/93 PostgreSQL PostgreSQL
.SH NAME .SH NAME
cluster - give storage clustering advice to Postgres cluster - give storage clustering advice to Postgres
@ -51,9 +51,10 @@ of a big table will not fit in the cache.
Another way is to use SELECT ... INTO TABLE temp FROM ...ORDER BY ... Another way is to use SELECT ... INTO TABLE temp FROM ...ORDER BY ...
This uses the PostgreSQL sorting code in ORDER BY to match the index, This uses the PostgreSQL sorting code in ORDER BY to match the index,
and is much faster for unordered data. You then drop the old table, use and is much faster for unordered data. You then drop the old table, use
ALTER TABLE RENAME to rename 'temp' to the old name, and recreate the ALTER TABLE RENAME to rename 'temp' to the old name, and recreate the b
indexes. From then on, CLUSTER should be fast because most of the heap bindexes. The only problem is that oids will not be preserved. From
data has been already ordered. then on, CLUSTER should be fast because most of the heap data has
already been ordered, and the existing index is used.
.SH EXAMPLE .SH EXAMPLE
.nf .nf
/* /*