On May 15, 2010, at 8:00 PM, Tom Lane wrote:
Tom Duffey <tduffey@xxxxxxxxxxxxxx> writes:
On May 15, 2010, at 7:28 PM, Tom Lane wrote:
Well, I tried executing a large "copy (select ...)" query and
couldn't
see any memory bloat at all in either the backend or psql. So
there's
something relevant that you haven't told us.
I hope you are right! The actual query is different because I was
not
aware until right before I posted this question that you can have a
WHERE clause with COPY. Here is the actual query I ran:
SELECT point_id || E'\t' || status || E'\t' || value || E'\t' ||
timestamp
FROM point_history
WHERE timestamp > NOW() - interval '18 months';
Ermm ... is that the whole query, or did you wrap it in COPY (...) TO
STDOUT? The former case will cause psql to eat memory, because it
tries
to buffer the whole result of an ordinary query. In the latter case
psql will just stream the data through to the output file.
That's the whole query. If I understand your reply correctly it
sounds like psql was the culprit and that I should try again using
COPY (...) TO STDOUT, no?
Tom
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