Re: Why are tables sizes so big?

From: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
To: Richard Huxton <dev(at)archonet(dot)com>
Cc: silicontao_roy(at)technologist(dot)com, pgsql-general(at)postgresql(dot)org
Subject: Re: Why are tables sizes so big?
Date: 2001-03-07 15:42:46
Message-ID: 9480.983979766@sss.pgh.pa.us
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Richard Huxton <dev(at)archonet(dot)com> writes:
>> The CSV file has 5 text fields that I change to char size 10, float, float,
>> int and float. That in it's self sould make the data on the server much
>> smaller, but it is not, it is bigger, why?

> char = 10 + 4
> floats= 8 * 3
> int = 4
> oid = 4

> That's at least 46 bytes per row plus indexes - which can take up a lot.

Actually, the per-row overhead is not just an OID: there are several
other system fields too. On a typical machine it's going to be 32 bytes
not four. Possibly more if you have nulls in the row; see
src/include/access/htup.h if you're interested.

regards, tom lane

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