Re: Quickly calculating row size of a table?

On Mon, Oct 17, 2005 at 04:42:15PM -0700, Jared Evans wrote:
> Is there a way for me to quickly calculate the maximum size of a row
> for a table? I wanted to know if there was an automatic way to do it
> before I do it manually.

Well, if the table is well-vacuumed, SELECT relpages*8192/reltuples from
pg_class will give you a good idea (assuming a default 8K page size),
but of course it's not perfect.

The only way I know of to get row length info for certain is vacuum full
verbose:

decibel=# vacuum full verbose rrs;
INFO: vacuuming "rrs.rrs"
INFO: "rrs": found 0 removable, 7 nonremovable row versions in 1 pages
DETAIL: 0 dead row versions cannot be removed yet.
Nonremovable row versions range from 61 to 73 bytes long.
--
Jim C. Nasby, Sr. Engineering Consultant jnasby(at)pervasive(dot)com
Pervasive Software http://pervasive.com work: 512-231-6117
vcard: http://jim.nasby.net/pervasive.vcf cell: 512-569-9461