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Commitf204274

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Update TODO for short header versions:
< 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
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‎doc/TODO‎

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PostgreSQL TODO List
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====================
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Current maintainer:Bruce Momjian (bruce@momjian.us)
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Last updated:Thu Sep14 17:43:58 EDT 2006
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Last updated:Sat Sep16 18:06:27 EDT 2006
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The most recent version of this document can be viewed at
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http://www.postgresql.org/docs/faqs.TODO.html.
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* Consider ways of storing rows more compactly on disk
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o Reorder physical storage order to reduce padding?
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This involves having the user-specified order of columns
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be different from the physical order. SELECT * would
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need to reorder the physical values to match the
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user-specified ordering.
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o Store disk pages with no alignment/padding?
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This necessitates adding CPU-required padding when moving
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rows from disk to memory.
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o Support a smaller header for short variable-length fields?
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One idea is to store the header in network byte order (high bits
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first), and read the high bits to determine the header length.
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http://archives.postgresql.org/pgsql-hackers/2006-09/msg00848.php
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One idea is to create zero-or-one-byte-header versions
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of varlena data types. In involves setting the high-bit and
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0-127 length in the single-byte header, or clear the high bit
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and store the 7-bit ASCII value in the rest of the byte.
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The small-header versions have no alignment requirements.
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http://archives.postgresql.org/pgsql-hackers/2006-09/msg01372.php
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o Reduce the row header size?
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‎doc/src/FAQ/TODO.html‎

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<bodybgcolor="#FFFFFF"text="#000000"link="#FF0000"vlink="#A00000"alink="#0000FF">
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<h1><aname="section_1">PostgreSQL TODO List</a></h1>
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<p>Current maintainer: Bruce Momjian (<ahref="mailto:bruce@momjian.us">bruce@momjian.us</a>)<br/>
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Last updated:Thu Sep14 17:43:58 EDT 2006
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Last updated:Sat Sep16 18:06:27 EDT 2006
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</p>
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<p>The most recent version of this document can be viewed at<br/>
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<ahref="http://www.postgresql.org/docs/faqs.TODO.html">http://www.postgresql.org/docs/faqs.TODO.html</a>.
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</p>
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</li><li>Consider ways of storing rows more compactly on disk
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<ul>
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<li>Reorder physical storage order to reduce padding?
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<p> This involves having the user-specified order of columns
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be different from the physical order. SELECT * would
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need to reorder the physical values to match the
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user-specified ordering.
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</p>
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</li><li>Store disk pages with no alignment/padding?
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<p> This necessitates adding CPU-required padding when moving
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rows from disk to memory.
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</p>
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</li><li>Support a smaller header for short variable-length fields?
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<p> One idea is to store the header in network byte order (high bits
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first), and read the high bits to determine the header length.
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<ahref="http://archives.postgresql.org/pgsql-hackers/2006-09/msg00848.php">http://archives.postgresql.org/pgsql-hackers/2006-09/msg00848.php</a>
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<li>Support a smaller header for short variable-length fields?
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<p> One idea is to create zero-or-one-byte-header versions
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of varlena data types. In involves setting the high-bit and
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0-127 length in the single-byte header, or clear the high bit
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and store the 7-bit ASCII value in the rest of the byte.
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The small-header versions have no alignment requirements.
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<ahref="http://archives.postgresql.org/pgsql-hackers/2006-09/msg01372.php">http://archives.postgresql.org/pgsql-hackers/2006-09/msg01372.php</a>
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</p>
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</li><li>Reduce the row header size?
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</li></ul>

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