Frequently Asked Questions (FAQ) for PostgreSQL
- Last updated: Tue May 22 17:50:25 EDT 2001
+ Last updated: Wed May 30 18:57:52 EDT 2001
Current maintainer: Bruce Momjian (pgman@candle.pha.pa.us)
column statistics on its own, so VACUUM ANALYZE must be run to collect
them periodically.
- Indexes are usually not used for ORDER BY operations: 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.
+ 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.
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
alink="#0000FF">
<H1>Frequently Asked Questions (FAQ) for PostgreSQL</H1>
- <P>Last updated: Tue May 22 17:50:25 EDT 2001</P>
+ <P>Last updated: Wed May 30 18:57:52 EDT 2001</P>
<P>Current maintainer: Bruce Momjian (<A href=
"mailto:pgman@candle.pha.pa.us">pgman@candle.pha.pa.us</A>)<BR>
periodically.</P>
<P>Indexes are usually not used for <SMALL>ORDER BY</SMALL>
- operations: a sequential scan followed by an explicit sort is
+ 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>