Kyle <kaf@nwlink.com> writes:
> I'm getting poor performance on 7.1 as compared to 7.0.
Hm. I don't know why 7.1 might be slower for plain SELECTs (the WAL
changes would certainly not affect that). Could you compile 7.1 for
profiling ("make clean; make PROFILE=-pg all" in the src/backend
subdirectory should do it) and send along a gprof table for your
test run?
> I've got a btree index on the first 16 of the data elements, and
> explain verifies that the index is used.
Simple explain doesn't prove that the index is being fully used ---
the display doesn't distinguish how many index columns are actually
being looked at. EXPLAIN VERBOSE output would resolve that doubt.
regards, tom lane