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Postgres FD Implementation
Commit 9e9a844f authored by Bruce Momjian's avatar Bruce Momjian
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* Allow star join optimizations

  While our bitmap scan allows multiple indexes to be joined to get
  to heap rows, a star joins allows multiple dimension _tables_ to
  be joined to index into a larger main fact table.  The join is
  usually performed by either creating a cartesian product of all
  the dimmension tables and doing a single join on that product or
  using subselects to create bitmaps of each dimmension table match
  and merge the bitmaps to perform the join on the fact table.
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doc/TODO
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PostgreSQL TODO List
====================
Current maintainer: Bruce Momjian (pgman@candle.pha.pa.us)
Last updated: Sat Dec 17 09:18:30 EST 2005
Last updated: Sat Dec 17 11:43:02 EST 2005
The most recent version of this document can be viewed at
http://www.postgresql.org/docs/faqs.TODO.html.
......@@ -1028,6 +1028,15 @@ Optimizer / Executor
* Log statements where the optimizer row estimates were dramatically
different from the number of rows actually found?
* Allow star join optimizations
While our bitmap scan allows multiple indexes to be joined to get
to heap rows, a star joins allows multiple dimension _tables_ to
be joined to index into a larger main fact table. The join is
usually performed by either creating a cartesian product of all
the dimmension tables and doing a single join on that product or
using subselects to create bitmaps of each dimmension table match
and merge the bitmaps to perform the join on the fact table.
Miscellaneous Performance
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doc/src/FAQ/TODO.html
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<body bgcolor="#FFFFFF" text="#000000" link="#FF0000" vlink="#A00000" alink="#0000FF">
<h1><a name="section_1">PostgreSQL TODO List</a></h1>
<p>Current maintainer: Bruce Momjian (<a href="mailto:pgman@candle.pha.pa.us">pgman@candle.pha.pa.us</a>)<br/>
Last updated: Sat Dec 17 09:18:30 EST 2005
Last updated: Sat Dec 17 11:43:02 EST 2005
</p>
<p>The most recent version of this document can be viewed at<br/>
<a href="http://www.postgresql.org/docs/faqs.TODO.html">http://www.postgresql.org/docs/faqs.TODO.html</a>.
......@@ -933,6 +933,15 @@ first.
</p>
</li><li>Log statements where the optimizer row estimates were dramatically
different from the number of rows actually found?
</li><li>Allow star join optimizations
<p> While our bitmap scan allows multiple indexes to be joined to get
to heap rows, a star joins allows multiple dimension _tables_ to
be joined to index into a larger main fact table. The join is
usually performed by either creating a cartesian product of all
the dimmension tables and doing a single join on that product or
using subselects to create bitmaps of each dimmension table match
and merge the bitmaps to perform the join on the fact table.
</p>
</li></ul>
<h1><a name="section_21">Miscellaneous Performance</a></h1>
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