Greg Stark <gsstark@mit.edu> writes:
> Tom Lane <tgl@sss.pgh.pa.us> 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