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Add all heap page rows visible bitmap idea: 

<   the heap.  One way to allow this is to set a bit to index tuples
>   the heap.  One way to allow this is to set a bit on index tuples
<   be cleared when a heap tuple is expired.
<
>   be cleared when a heap tuple is expired.  Another idea is to maintain
>   a bitmap of heap pages where all rows are visible to all backends,
>   and allow index lookups to reference that bitmap to avoid heap
>   lookups, perhaps the same bitmap we might add someday to determine
>   which heap pages need vacuuming.
This commit is contained in:
Bruce Momjian 2005-12-01 22:30:43 +00:00
parent 915fb7f687
commit 113ece8f3d
2 changed files with 14 additions and 7 deletions
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11
doc/TODO
View File

@ -2,7 +2,7 @@
PostgreSQL TODO List
====================
Current maintainer: Bruce Momjian (pgman@candle.pha.pa.us)
Last updated: Thu Dec 1 17:12:27 EST 2005
Last updated: Thu Dec 1 17:30:23 EST 2005
The most recent version of this document can be viewed at
http://www.postgresql.org/docs/faqs.TODO.html.
@ -859,11 +859,14 @@ Cache Usage
Currently indexes do not have enough tuple visibility information
to allow data to be pulled from the index without also accessing
the heap. One way to allow this is to set a bit to index tuples
the heap. One way to allow this is to set a bit on index tuples
to indicate if a tuple is currently visible to all transactions
when the first valid heap lookup happens. This bit would have to
be cleared when a heap tuple is expired.
be cleared when a heap tuple is expired. Another idea is to maintain
a bitmap of heap pages where all rows are visible to all backends,
and allow index lookups to reference that bitmap to avoid heap
lookups, perhaps the same bitmap we might add someday to determine
which heap pages need vacuuming.
* Consider automatic caching of queries at various levels:

10
doc/src/FAQ/TODO.html
View File

@ -8,7 +8,7 @@
<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: Thu Dec 1 17:12:27 EST 2005
Last updated: Thu Dec 1 17:30:23 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>.
@ -778,10 +778,14 @@ first.
</li><li>Allow data to be pulled directly from indexes
<p> Currently indexes do not have enough tuple visibility information
to allow data to be pulled from the index without also accessing
the heap. One way to allow this is to set a bit to index tuples
the heap. One way to allow this is to set a bit on index tuples
to indicate if a tuple is currently visible to all transactions
when the first valid heap lookup happens. This bit would have to
be cleared when a heap tuple is expired.
be cleared when a heap tuple is expired. Another idea is to maintain
a bitmap of heap pages where all rows are visible to all backends,
and allow index lookups to reference that bitmap to avoid heap
lookups, perhaps the same bitmap we might add someday to determine
which heap pages need vacuuming.
</p>
</li><li>Consider automatic caching of queries at various levels:
<ul>