Re: Tuple data
Michael Richards <miker@interchange.ca>
From: "Michael Richards" <miker@interchange.ca>
To: "Tom Lane" <tgl@sss.pgh.pa.us>
Cc: <pgsql-hackers@postgresql.org>
Date: 2000-12-16T20:14:29Z
Lists: pgsql-hackers
> That's not right --- AFAIR there is no length in the tuple data. You > must use the length from the 'page item' pointer that points to this > tuple if you want to know the total tuple length. Oops, I meant attribute length... > If you were testing with tables containing single varlena columns, then > you may have seen the varlena datum's length word and taken it for total > length of the tuple --- but it's only total length of that one column. Yes, I obviously had assumed that this length was common to all types (I was testing with varchars before). I presume then that I get the sizes based on some system tables. What query should I run to give me the layout (in the order it's on disk) and the size of each non-varlen attribute? > Your example dump looks like F24D 0000 is userid, FFFF FFFF is folderid, > and 1300 0000 is the varlena length word for foldername. This is correct. thanks -Michael