On 13/07/10 17:18, Andras Fabian wrote:
> But still no definitive clue about the reasons. What is also quite interesting is, that when I start my
COPY-to-STDOUTexperiment, it is running quite fast in the beginning. Sometimes up to 400 Mbytes, sometimes up to 1.4
GBytes(I didn't find a real reason which I could be correlated to this) ... and then, suddenly it begins to stall. From
thereon, it only advances slowly with all the congestion_wait going on ... Hmm, maybe it has really something to do
withthe state of the memory ... (this would go well with the fact, that a freshly rebooted server is not having the
problemin the beginning).
Is there any chance something is buffering the output of the COPY ... TO
STDOUT? Whether it's a pipe/socket buffer that grows to a certain limit,
then begins to be limited by the ability of the receiver to empty it, or
whether it's the receiver buffering the whole COPY in memory before
writing it out, I don't know.
Do you see anything growing in memory use on the system while the COPY
is in progress? Any of the memory use stats in "free -m" changing"?
--
Craig Ringer
