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compressed bitvectors for postgresql (and perl, php, etc)

From: "Flynn" <tech(at)vtech(dot)fr>
To: <pgsql-patches(at)postgresql(dot)org>
Subject: compressed bitvectors for postgresql (and perl, php, etc)
Date: 2004-11-26 14:07:09
Message-ID: 0dfa01c4d3c1$3a215b70$a816a8c0@vtech.fr (view raw or flat)
Thread:
Lists: pgsql-patches
Hello everyone

Although this is not a patch,  I have developped a set of
user-defined function to deal with compressed bitvectors,
which are the same than bit varying but much smaller
since they are compressed.

Since I am in a process to migrate my applications from mysql to postgresql,
they are juste made available for postgresql there :
  http://www.vtech.fr/opensource (hope links are ok here?)

They are designed in such a way that setting or resetting a bit in the
bit array can be done without having to uncompress/recompress the bitvector.
In some cases, they might be faster than bit varying, since bitwise
operations
are dealt with on a block-by-block basis.

They have serious limitations, the main one being that bit-indexes must be
kept
in the range [0-8388599]

I'm glad to give that away to this community, although I humbly am eager to
get
some feedback to realize if this compressed bitvector notion is of any help
to someone else than myself :)

Rgds,
Jean "flynn" Flinois



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