Josh Berkus <[EMAIL PROTECTED]> writes: >> I've got a quad 2.8Ghz MP Xeon (IBM x445) that I could test on. Does >> anyone have a test set that can reliably reproduce the problem?
> Unfortunately we can't seem to come up with one. > It does seem to require a database which is in the many GB (> 10GB), and a > situation where a small subset of the data is getting hit repeatedly by > multiple processes. I do not think a large database is actually necessary; the test case Josh's client has is only hitting a relatively small amount of data. The trick seems to be to cause lots and lots of ReadBuffer/ReleaseBuffer activity without much else happening, and to do this from multiple backends concurrently. I believe the best way to make this happen is a lot of relatively simple (but not short) indexscan queries that in aggregate touch just a bit less than shared_buffers worth of data. I have not tried to make a self-contained test case, but based on what I know now I think it should be possible. I'll give this a shot later tonight --- it does seem that trying to reproduce the problem on different kinds of hardware is the next useful step we can take. regards, tom lane ---------------------------(end of broadcast)--------------------------- TIP 4: Don't 'kill -9' the postmaster