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1 parenta00d6b2 commit1a2be80Copy full SHA for 1a2be80
doc/src/sgml/release.sgml
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<!--
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-$Header: /cvsroot/pgsql/doc/src/sgml/release.sgml,v 1.218 2003/10/27 02:51:39 momjian Exp $
+$Header: /cvsroot/pgsql/doc/src/sgml/release.sgml,v 1.219 2003/10/29 20:38:19 momjian Exp $
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-->
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<appendix id="release">
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<glossentry><glossterm> Performance</glossterm>
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<glossdef><para> IN/NOT IN subqueries are now much more efficient
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+ <footnote>
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+ <para>
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+ In previous releases, IN/NOT IN subqueries were joined to the
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+ upper query by sequentially scanning the subquery looking for
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+ a join. The 7.4 code uses the same sophisticated techniques
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+ used by ordinary joins and so is much faster, and is now faster
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+ than EXISTS subqueries.
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+ </para>
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+ </footnote>
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</para>
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<para> Improved GROUP BY processing by using hash buckets</para>