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| author | Bruce Momjian <bruce@momjian.us> | 1998-03-14 22:55:21 +0000 |
|---|---|---|
| committer | Bruce Momjian <bruce@momjian.us> | 1998-03-14 22:55:21 +0000 |
| commit | 006fd9253f147b3fa5525bb42c31cec1f7760e3c (patch) | |
| tree | a8afbbdfa32eda78892b621347b61c6b99c8d645 /src | |
| parent | 3674ccdf95037c0dcbfcae38f02bf3fdd2080acd (diff) | |
| download | postgresql-006fd9253f147b3fa5525bb42c31cec1f7760e3c.tar.gz postgresql-006fd9253f147b3fa5525bb42c31cec1f7760e3c.zip | |
Cluster fixup.
Diffstat (limited to 'src')
| -rw-r--r-- | src/man/cluster.l | 13 |
1 files changed, 7 insertions, 6 deletions
diff --git a/src/man/cluster.l b/src/man/cluster.l index e76796e61f8..ac28969e086 100644 --- a/src/man/cluster.l +++ b/src/man/cluster.l @@ -1,6 +1,6 @@ .\" This is -*-nroff-*- .\" XXX standard disclaimer belongs here.... -.\" $Header: /cvsroot/pgsql/src/man/Attic/cluster.l,v 1.5 1998/03/14 21:57:56 momjian Exp $ +.\" $Header: /cvsroot/pgsql/src/man/Attic/cluster.l,v 1.6 1998/03/14 22:55:21 momjian Exp $ .TH CLUSTER SQL 01/23/93 PostgreSQL PostgreSQL .SH NAME cluster - give storage clustering advice to Postgres @@ -48,11 +48,12 @@ unordered, the entries are on random pages, so there is one disk page retrieved for every row moved. PostgreSQL has a cache, but the majority of a big table will not fit in the cache. .PP -Another way is to use SELECT ... INTO TABLE temp FROM ... This uses the -PostgreSQL sorting code, 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 indexes. From then on, CLUSTER should be -fast because most of the heap data is ordered. +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, +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 +indexes. From then on, CLUSTER should be fast because most of the heap +data has been already ordered. .SH EXAMPLE .nf /* |