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80 lines
2.2 KiB
Plaintext
80 lines
2.2 KiB
Plaintext
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$Header: /cvsroot/pgsql/doc/src/sgml/Attic/populate.sgml,v 2.3 2000/09/29 20:21:34 petere Exp $
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-->
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<chapter id="populate">
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<title>Populating a Database</title>
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<note>
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<title>Author</title>
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<para>
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Written by Tom Lane, from an e-mail message dated 1999-12-05.
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</para>
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</note>
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<para>
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One may need to do a large number of table insertions when first
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populating a database. Here are some tips and techniques for making that as
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efficient as possible.
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</para>
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<sect1 id="disable-autocommit">
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<title>Disable Auto-commit</title>
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<para>
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Turn off auto-commit and just do one commit at
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the end. Otherwise <productname>Postgres</productname> is doing a
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lot of work for each record
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added. In general when you are doing bulk inserts, you want
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to turn off some of the database features to gain speed.
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</para>
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</sect1>
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<sect1 id="populate-copy-from">
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<title>Use COPY FROM</title>
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<para>
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Use <command>COPY FROM STDIN</command> to load all the records in one
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command, instead
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of a series of INSERT commands. This reduces parsing, planning, etc
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overhead a great deal. If you do this then it's not necessary to fool
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around with autocommit.
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</para>
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</sect1>
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<sect1 id="populate-rm-indices">
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<title>Remove Indices</title>
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<para>
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If you are loading a freshly created table, the fastest way is to
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create the table, bulk-load with COPY, then create any indexes needed
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for the table. Creating an index on pre-existing data is quicker than
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updating it incrementally as each record is loaded.
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</para>
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<para>
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If you are augmenting an existing table, you can <command>DROP
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INDEX</command>, load the table, then recreate the index. Of
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course, the database performance for other users may be adversely
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affected during the time that the index is missing.
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</para>
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</sect1>
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</chapter>
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<!-- Keep this comment at the end of the file
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Local variables:
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mode:sgml
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sgml-omittag:nil
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sgml-shorttag:t
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sgml-minimize-attributes:nil
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sgml-always-quote-attributes:t
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sgml-indent-step:1
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sgml-indent-data:t
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sgml-parent-document:nil
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sgml-default-dtd-file:"./reference.ced"
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sgml-exposed-tags:nil
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sgml-local-catalogs:("/usr/lib/sgml/catalog")
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sgml-local-ecat-files:nil
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End:
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-->
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