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Re: [HACKERS] Large databases, performance

From: "Zeugswetter Andreas SB SD" <ZeugswetterA(at)spardat(dot)at>
To: "Manfred Koizar" <mkoi-pg(at)aon(dot)at>,<shridhar_daithankar(at)persistent(dot)co(dot)in>
Cc: <pgsql-hackers(at)postgresql(dot)org>,"pgsql-general" <pgsql-general(at)postgresql(dot)org>,<pgsql-performance(at)postgresql(dot)org>
Subject: Re: [HACKERS] Large databases, performance
Date: 2002-10-07 15:42:12
Message-ID: 46C15C39FEB2C44BA555E356FBCD6FA4887A5A@m0114.s-mxs.net (view raw or flat)
Thread:
Lists: pgsql-generalpgsql-hackerspgsql-performance
> if i'm not mistaken, a char(n)/varchar(n) column is stored as a 32-bit
> integer specifying the length followed by as many characters as the
> length tells.  On 32-bit Intel hardware this structure is aligned on a
> 4-byte boundary.

Yes.

> | opc0     char (3)   no    no       8     4
> | opc1     char (3)   no    no       8     4
> | opc2     char (3)   no    no       8     4

> Hackers, do you think it's possible to hack together a quick and dirty
> patch, so that string length is represented by one byte?  IOW can a
> database be built that doesn't contain any char/varchar/text value
> longer than 255 characters in the catalog?

Since he is only using fixchar how about doing a fixchar implemetation, that 
does not store length at all ? It is the same for every row anyways !

Andreas

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