hubert depesz lubaczewski wrote:
On 3/2/07, Kenneth Downs <ken@xxxxxxxxxx> wrote:
This reminds me of another advantage of the WITH RECURSIVE, which is
that it pushes to overhead to SELECT, with no associated write-time
overheads.
hmm .. why do you consider this as advantage? i would say it's rather
drawback.
One school of thought aims for overall system performance gains by
keeping transactions as small as possible. WITH RECURSIVE allows an
UPDATE to affect exactly one row, where other methods affect more rows.
Therefore the WITH RECURSIVE gives you the smallest possible transaction
at write time.
Further, it seems the actual number of rows pulled in all approaches
should be the same, so now I wonder if there really even is any overhead
at SELECT time, making the argument for WITH RECURSIVE rather conclusive
I'd say.
depesz
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--
Kenneth Downs
Secure Data Software, Inc.
www.secdat.com / www.andromeda-project.org
Office: 631-689-7200 Cell: 631-379-0010
::Think you may have a problem with programming? Ask yourself this
::question: do you worry about how to throw away a garbage can?
