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Update TODO for short header versions:

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< 	o Reorder physical storage order to reduce padding?
<
< 	  This involves having the user-specified order of columns
< 	  be different from the physical order.  SELECT * would
< 	  need to reorder the physical values to match the
< 	  user-specified ordering.
<
< 	o Store disk pages with no alignment/padding?
<
< 	  This necessitates adding CPU-required padding when moving
< 	  rows from disk to memory.
<
< 	  One idea is to store the header in network byte order (high bits
< 	  first), and read the high bits to determine the header length.
< 	  http://archives.postgresql.org/pgsql-hackers/2006-09/msg00848.php
> 	  One idea is to create zero-or-one-byte-header versions
> 	  of varlena data types.  In involves setting the high-bit and
> 	  0-127 length in the single-byte header, or clear the high bit
> 	  and store the 7-bit ASCII value in the rest of the byte.
> 	  The small-header versions have no alignment requirements.
> 	  http://archives.postgresql.org/pgsql-hackers/2006-09/msg01372.php
This commit is contained in:
Bruce Momjian
2006-09-16 22:06:54 +00:00
parent 5ff4f39c0e
commit f204274191
2 changed files with 15 additions and 31 deletions
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23
doc/TODO
View File

@ -2,7 +2,7 @@
PostgreSQL TODO List PostgreSQL TODO List
==================== ====================
Current maintainer: Bruce Momjian (bruce@momjian.us) Current maintainer: Bruce Momjian (bruce@momjian.us)
Last updated: Thu Sep 14 17:43:58 EDT 2006 Last updated: Sat Sep 16 18:06:27 EDT 2006
The most recent version of this document can be viewed at The most recent version of this document can be viewed at
http://www.postgresql.org/docs/faqs.TODO.html. http://www.postgresql.org/docs/faqs.TODO.html.
@ -1353,23 +1353,14 @@ Miscellaneous Performance
* Consider ways of storing rows more compactly on disk * Consider ways of storing rows more compactly on disk
o Reorder physical storage order to reduce padding?
This involves having the user-specified order of columns
be different from the physical order. SELECT * would
need to reorder the physical values to match the
user-specified ordering.
o Store disk pages with no alignment/padding?
This necessitates adding CPU-required padding when moving
rows from disk to memory.
o Support a smaller header for short variable-length fields? o Support a smaller header for short variable-length fields?
One idea is to store the header in network byte order (high bits One idea is to create zero-or-one-byte-header versions
first), and read the high bits to determine the header length. of varlena data types. In involves setting the high-bit and
http://archives.postgresql.org/pgsql-hackers/2006-09/msg00848.php 0-127 length in the single-byte header, or clear the high bit
and store the 7-bit ASCII value in the rest of the byte.
The small-header versions have no alignment requirements.
http://archives.postgresql.org/pgsql-hackers/2006-09/msg01372.php
o Reduce the row header size? o Reduce the row header size?

23
doc/src/FAQ/TODO.html
View File

@ -8,7 +8,7 @@
<body bgcolor="#FFFFFF" text="#000000" link="#FF0000" vlink="#A00000" alink="#0000FF"> <body bgcolor="#FFFFFF" text="#000000" link="#FF0000" vlink="#A00000" alink="#0000FF">
<h1><a name="section_1">PostgreSQL TODO List</a></h1> <h1><a name="section_1">PostgreSQL TODO List</a></h1>
<p>Current maintainer: Bruce Momjian (<a href="mailto:bruce@momjian.us">bruce@momjian.us</a>)<br/> <p>Current maintainer: Bruce Momjian (<a href="mailto:bruce@momjian.us">bruce@momjian.us</a>)<br/>
Last updated: Thu Sep 14 17:43:58 EDT 2006 Last updated: Sat Sep 16 18:06:27 EDT 2006
</p> </p>
<p>The most recent version of this document can be viewed at<br/> <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>. <a href="http://www.postgresql.org/docs/faqs.TODO.html">http://www.postgresql.org/docs/faqs.TODO.html</a>.
@ -1219,20 +1219,13 @@ first.
</p> </p>
</li><li>Consider ways of storing rows more compactly on disk </li><li>Consider ways of storing rows more compactly on disk
<ul> <ul>
<li>Reorder physical storage order to reduce padding? <li>Support a smaller header for short variable-length fields?
<p> This involves having the user-specified order of columns <p> One idea is to create zero-or-one-byte-header versions
be different from the physical order. SELECT * would of varlena data types. In involves setting the high-bit and
need to reorder the physical values to match the 0-127 length in the single-byte header, or clear the high bit
user-specified ordering. and store the 7-bit ASCII value in the rest of the byte.
</p> The small-header versions have no alignment requirements.
</li><li>Store disk pages with no alignment/padding? <a href="http://archives.postgresql.org/pgsql-hackers/2006-09/msg01372.php">http://archives.postgresql.org/pgsql-hackers/2006-09/msg01372.php</a>
<p> This necessitates adding CPU-required padding when moving
rows from disk to memory.
</p>
</li><li>Support a smaller header for short variable-length fields?
<p> One idea is to store the header in network byte order (high bits
first), and read the high bits to determine the header length.
<a href="http://archives.postgresql.org/pgsql-hackers/2006-09/msg00848.php">http://archives.postgresql.org/pgsql-hackers/2006-09/msg00848.php</a>
</p> </p>
</li><li>Reduce the row header size? </li><li>Reduce the row header size?
</li></ul> </li></ul>