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Cluster fixup.
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src/man/cluster.l

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.\" This is -*-nroff-*-
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.\" XXX standard disclaimer belongs here....
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.\" $Header: /cvsroot/pgsql/src/man/Attic/cluster.l,v 1.5 1998/03/14 21:57:56 momjian Exp $
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.\" $Header: /cvsroot/pgsql/src/man/Attic/cluster.l,v 1.6 1998/03/14 22:55:21 momjian Exp $
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.TH CLUSTER SQL 01/23/93 PostgreSQL PostgreSQL
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.SH NAME
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cluster - give storage clustering advice to Postgres
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retrieved for every row moved. PostgreSQL has a cache, but the majority
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of a big table will not fit in the cache.
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.PP
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Another way is to use SELECT ... INTO TABLE temp FROM ... This uses the
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PostgreSQL sorting code, and is much faster for unordered data. You
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then drop the old table, use ALTER TABLE RENAME to rename 'temp' to the
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old name, and recreate the indexes. From then on, CLUSTER should be
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fast because most of the heap data is ordered.
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Another way is to use SELECT ... INTO TABLE temp FROM ...ORDER BY ...
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This uses the PostgreSQL sorting code in ORDER BY to match the index,
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and is much faster for unordered data. You then drop the old table, use
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ALTER TABLE RENAME to rename 'temp' to the old name, and recreate the
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indexes. From then on, CLUSTER should be fast because most of the heap
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data has been already ordered.
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.SH EXAMPLE
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.nf
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/*

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