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<appendix id="release">
<glossentry><glossterm> Performance</glossterm>
<glossdef><para> IN/NOT IN subqueries are now much more efficient
+ <footnote>
+ <para>
+ In previous releases, IN/NOT IN subqueries were joined to the
+ upper query by sequentially scanning the subquery looking for
+ a join. The 7.4 code uses the same sophisticated techniques
+ used by ordinary joins and so is much faster, and is now faster
+ than EXISTS subqueries.
+ </para>
+ </footnote>
</para>
<para> Improved GROUP BY processing by using hash buckets</para>