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
arrayinto a function and have the function tell me exactly how much space that would require on-disk. It's pretty easy
tofigure that out for things like varchar and numeric, but doing so for arrays or composite types requires pretty
detailedknowledge 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.
--
Álvaro Herrera <alvherre@commandprompt.com>
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