Dne 09.10.2012 11:48, Craig Ringer napsal:
On 10/06/2012 08:45 AM, Liam Caffrey wrote:
Hi,
If I run a CTE does that materialize the resulting data in the same
(or
a similar) way as if I created a temp table and referred to that
instead? Or does the CTE keep the set in memory?
Really good question, I too would be interested in this.
I'd expect it'd materialize to RAM if the result is within `work_mem`
but I'd love to know for sure.
Yes - it's using a tuplestore, and that's the default behavior. It
stores the
tuples in RAM until it reaches work_mem and then starts spilling the
data
to disk. It's entirely transparent behavior.
Tomas
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