Simon Riggs wrote:
On Fri, 2007-05-11 at 22:59 +0100, Heikki Linnakangas wrote:
For comparison, here's the test results with vanilla CVS HEAD:
copy-head | 00:06:21.533137
copy-head | 00:05:54.141285
I'm slightly worried that the results for COPY aren't anywhere near as
good as the SELECT and VACUUM results. It isn't clear from those numbers
that the benefit really is significant.
Agreed, the benefit isn't clear.
Are you thinking that having COPY avoid cache spoiling is a benefit just
of itself? Or do you see a pattern of benefit from your other runs?
I think it's worth having just to avoid cache spoiling. I wouldn't
bother otherwise, but since we have the infrastructure for vacuum and
large seqscans, we might as well use it for COPY as well.
(BTW what was wal_buffers set to? At least twice the ring buffer size,
hopefully).
Good question. [checks]. wal_buffers was set to 128KB. I tried raising
it to 1MB, but it didn't make any difference.
--
Heikki Linnakangas
EnterpriseDB http://www.enterprisedb.com
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