jao@xxxxxxxxxxxx writes: > I have this table and index: > create table t(id int, hash int); > create index idx_t on t(hash); > The value of the hash column, which is indexed, is a pseudo-random > number. I load the table and measure the time per insert. > What I've observed is that inserts slow down as the table grows to > 1,000,000 records. Observing the pg_stat* tables, I see that the data > page reads per unit time stay steady, but that index page reads grow > quickly, (shared_buffers was set to 2000). Define "quickly" ... the expected behavior is that cost to insert into a btree index grows roughly as log(N). Are you seeing anything worse than that? shared_buffers of 2000 is generally considered too small for high-volume databases. Numbers like 10000-50000 are considered reasonable on modern hardware. It's possible that you could go larger without too much penalty if using the 8.1 buffer manager code, but I don't know if anyone has benchmarked that systematically. regards, tom lane
