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>23.2. Routine Reindexing</A
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> In some situations it is worthwhile to rebuild indexes periodically
with the <A
HREF="sql-reindex.html"
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>
command.
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> B-tree index pages that have become completely empty are reclaimed for
re-use. However, there is still a possibility
of inefficient use of space: if all but a few index keys on a page have
been deleted, the page remains allocated. Therefore, a usage
pattern in which most, but not all, keys in each range are eventually
deleted will see poor use of space. For such usage patterns,
periodic reindexing is recommended.
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> The potential for bloat in non-B-tree indexes has not been well
researched. It is a good idea to periodically monitor the index's physical
size when using any non-B-tree index type.
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> Also, for B-tree indexes, a freshly-constructed index is slightly faster to
access than one that has been updated many times because logically
adjacent pages are usually also physically adjacent in a newly built index.
(This consideration does not apply to non-B-tree indexes.) It
might be worthwhile to reindex periodically just to improve access speed.
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