Hi,
according to
http://www.postgresql.org/docs/8.2/interactive/storage-toast.html:
EXTENDED allows both compression and out-of-line storage.
This is the default for most TOAST-able data types.
Compression will be attempted first, then out-of-line storage if the row
is still too big.
MAIN allows compression but not out-of-line storage.
(Actually, out-of-line storage will still be performed for such columns,
but only as a last resort when there is no other way to make the row
small enough.)
At the end of the day, the behaviour is the same, isn't it?
--
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Zoltán Böszörményi
Cybertec Geschwinde & Schönig GmbH
http://www.postgresql.at/