Re: size of a table on postgresql

aravind chandu wrote:
> Hello,
>
> The following is the procedure to calculate the disk space
> occupied by postgresql from a flat file.
>
> In this I didn't understood some terms
>
> 24 bytes: each row header (approximate)
> 24 bytes: one int field and one text field
> + 4 bytes: pointer on page to tuple
>
> here row header is taken as 24 bytes and in some sites it is given
> row header as 40 bytes and in some 32 bytes
> http://www.sbras.ru/rus/docs/db/postgres/doc/howto/faq-english.shtml#3.6
> http://www.softlab.ntua.gr/facilities/documentation/unix/postgres/faq-english.html
>
> Is the row header value is constant or it is variable?If so what could be the maximun value?
> what is that additional +4bytes as pointer on page to tuple.
>
> Should all these were fixed or is there any command to find the values for these fields?

Maybe you want:

http://www.postgresql.org/docs/8.3/interactive/functions-admin.html

pg_relation_size(text) Disk space used by the table or index with the
specified name. The table name can be qualified with a schema name

pg_total_relation_size(text) Total disk space used by the table with the
specified name, including indexes and toasted data. The table name can
be qualified with a schema name

?

Cheers
Tino