Horton

Re: [HACKERS] Large databases, performance

Zeugswetter Andreas DCP SD <zeugswettera@spardat.at>

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From: "Zeugswetter Andreas SB SD" <ZeugswetterA@spardat.at>
To: "Manfred Koizar" <mkoi-pg@aon.at>, <shridhar_daithankar@persistent.co.in>
Cc: <pgsql-hackers@postgresql.org>, "pgsql-general" <pgsql-general@postgresql.org>, <pgsql-performance@postgresql.org>
Date: 2002-10-07T15:42:12Z
Lists: pgsql-hackers, pgsql-performance, pgsql-general 
> 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