Note: Above test has been performed on Unpatched master with default values for checkpoint_flush_after, bgwriter_flush_after and wal_writer_flush_after.
On Thu, May 12, 2016 at 9:20 PM, Andres Freund <andres@anarazel.de> wrote:
On 2016-05-12 11:27:31 -0400, Robert Haas wrote: > On Thu, May 12, 2016 at 11:13 AM, Andres Freund <andres@anarazel.de> wrote: > > Could you run this one with a number of different backend_flush_after > > settings? I'm suspsecting the primary issue is that the default is too low. > > What values do you think would be good to test? Maybe provide 3 or 4 > suggested values to try?
I'm suspecting that only backend_flush_after_* has these negative performance implications at this point. One path is to increase that option's default value, another is to disable only backend guided flushing. And add a strong hint that if you care about predictable throughput you might want to enable it.
