Alvaro Herrera <alvhe...@commandprompt.com> writes: > Excerpts from Jim Nasby's message of mié feb 01 20:47:05 -0300 2012: >> I'm not certain this in what Pavel is referring to, but I have often wished >> that I could pass something like an array into a function and have the >> function tell me exactly how much space that would require on-disk. It's >> pretty easy to figure that out for things like varchar and numeric, but >> doing so for arrays or composite types requires pretty detailed knowledge of >> PG internals.
> I think you can just use pg_column_size on a composite datum (such as a > ROW() construct) and it will give you the right number. If it's a freshly-computed value, pg_column_size will give you the size of the "raw" datum. The actual size on disk might be less due to compression, but I don't think we give you any way to find that out short of actually storing it in a table. Note that the rangetype internal functions Pavel suggests we should expose won't give you the latter either. regards, tom lane -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers