Geoff Winkless wrote: [trying to account for the disk space used] > Of course I got that slightly wrong: ItemIdData is for each row, not for each > column; an extra 4 bytes > for each row makes the per-row space 290MB, leaving 167MB unexplained.
> I'm assuming the remaining 167MB is related to the alignment requirements, > although that does seem > quite a lot at 15 bytes per row (perhaps I'm just unfortunate with the data > sizes resulting in poor > alignment). > > I guess the answer to my question is that there is no answer to my question; > pg just does use a > massive (especially in relation to thin but tall tables) proportion of > diskspace for its own purposes. I doubt that PostgreSQL has substantially more disk overhead than other DBMS with comparable capabilities (comparison with flat files or MyISAM would be unfair). Have you tried using pg_filedump (http://pgfoundry.org/frs/?group_id=1000541) to dump a page or two of your table and figure out what is where and where the space went? Yours, Laurenz Albe -- Sent via pgsql-admin mailing list (pgsql-admin@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-admin
