Greg Stark <gsstark@xxxxxxx> writes: > Tom Lane <tgl@xxxxxxxxxxxxx> writes: >> That surprises me too --- can you provide details on the test case so >> other people can reproduce it? AFAIR the only performance difference >> between SERIALIZABLE and READ COMMITTED is the frequency with which >> transaction status snapshots are taken; your report suggests you were >> spending 30% of the time in GetSnapshotData, which is a lot higher than >> I've ever seen in a profile. > Perhaps it reduced the amount of i/o concurrent vacuums were doing? Can't see how it would do that. regards, tom lane
