Frequently Asked Questions (FAQ) for PostgreSQL
- Last updated: Sat Jan 29 23:02:37 EST 2005
+ Last updated: Sat Jan 29 23:04:53 EST 2005
Current maintainer: Bruce Momjian (pgman@candle.pha.pa.us)
4.4) What is the maximum size for a row, a table, and a database?
4.5) How much database disk space is required to store data from a
typical text file?
- 4.6) My queries are slow or don't make use of the indexes. Why?
+ 4.6) Why are my queries slow? Why don't they make use of indexes?
4.7) How do I see how the query optimizer is evaluating my query?
4.8) What is an R-tree index?
4.9) What is the Genetic Query Optimizer?
NULLs are stored as bitmaps, so they use very little space.
- 4.6) My queries are slow or don't make use of the indexes. Why?
+ 4.6) Why are my queries slow? Why don't they make use of indexes?
Indexes are not automatically used by every query. Indexes are only
used if the table is larger than a minimum size, and the query selects
alink="#0000ff">
<H1>Frequently Asked Questions (FAQ) for PostgreSQL</H1>
- <P>Last updated: Sat Jan 29 23:02:37 EST 2005</P>
+ <P>Last updated: Sat Jan 29 23:04:53 EST 2005</P>
<P>Current maintainer: Bruce Momjian (<A href=
"mailto:pgman@candle.pha.pa.us">pgman@candle.pha.pa.us</A>)<BR>
table, and a database?<BR>
<A href="#4.5">4.5</A>) How much database disk space is required
to store data from a typical text file?<BR>
- <A href="#4.6">4.6</A>) My queries are slow or don't make use of
- the indexes. Why?<BR>
+ <A href="#4.6">4.6</A>) Why are my queries slow? Why don't they
+ make use of indexes?<BR>
<A href="#4.7">4.7</A>) How do I see how the query optimizer is
evaluating my query?<BR>
<A href="#4.8">4.8</A>) What is an R-tree index?<BR>
<P><SMALL>NULL</SMALL>s are stored as bitmaps, so they
use very little space.</P>
- <H4><A name="4.6">4.6</A>) My queries are slow or don't make use of
- the indexes. Why?</H4>
+ <H4><A name="4.6">4.6</A>) Why are my queries slow? Why don't they
+ make use of indexes?</H4>
<P>Indexes are not automatically used by every query. Indexes are only
used if the table is larger than a minimum size, and the query