02.08.11 11:26, Robert Ayrapetyan написав(ла):
Seems this assumption is not right. Just created simple index on
bigint column - situation with huge performance
degradation repeated. Dropping this index solved COPY issues on the fly.
So I'm still convinced - this bug relates to FreeBSD 64-bit + UFS +
bigint column index
(some of these may be superfluous, but I have no resources to check on
different platforms with different filesystems).
Interrrresting. We also have FreeBSDx64 on UFS and are using bigint
(bigserial) keys. It seems I will need to perform more tests here
because I do see similar problems. I for sure can do a copy of data with
int4 keys and test the performance.
BTW: The thing we are going to try on next upgrade is to change UFS
block size from 16K to 8K. What problem I saw is that with default
setting, UFS needs to read additional 8K when postgresql writes it's
page (and for index random writes can be vital). Unfortunately, such a
changes requires partition reformat and I can't afford it for now.
Best regards, Vitalii Tymchyshyn
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