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Update FAQ.

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Bruce Momjian 2001-05-30 23:00:41 +00:00
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doc/FAQ
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Frequently Asked Questions (FAQ) for PostgreSQL
Last updated: Wed May 30 18:57:52 EDT 2001
Last updated: Wed May 30 19:00:33 EDT 2001
Current maintainer: Bruce Momjian (pgman@candle.pha.pa.us)
@ -709,9 +709,9 @@ Maximum number of indexes on a table? unlimited
column statistics on its own, so VACUUM ANALYZE must be run to collect
them periodically.
Indexes are usually not used for ORDER BY or joins: a sequential scan
Indexes are usually not used for ORDER BY or joins. A sequential scan
followed by an explicit sort is faster than an indexscan of all tuples
of a large table, because it takes fewer disk accesses.
of a large table. This is because random disk access is very slow.
When using wild-card operators such as LIKE or ~, indices can only be
used if the beginning of the search is anchored to the start of the

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doc/src/FAQ/FAQ.html
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alink="#0000FF">
<H1>Frequently Asked Questions (FAQ) for PostgreSQL</H1>
<P>Last updated: Wed May 30 18:57:52 EDT 2001</P>
<P>Last updated: Wed May 30 19:00:33 EDT 2001</P>
<P>Current maintainer: Bruce Momjian (<A href=
"mailto:pgman@candle.pha.pa.us">pgman@candle.pha.pa.us</A>)<BR>
@ -908,9 +908,9 @@ Maximum number of indexes on a table? unlimited
periodically.</P>
<P>Indexes are usually not used for <SMALL>ORDER BY</SMALL>
or joins: a sequential scan followed by an explicit sort is
faster than an indexscan of all tuples of a large table, because it
takes fewer disk accesses.</P>
or joins. A sequential scan followed by an explicit sort is
faster than an indexscan of all tuples of a large table. This
is because random disk access is very slow.</P>
<P>When using wild-card operators such as <SMALL>LIKE</SMALL> or
<I>~,</I> indices can only be used if the beginning of the search