Re: A little COPY speedup

"Tom Lane" <tgl@sss.pgh.pa.us> writes:

> "Simon Riggs" <simon@2ndquadrant.com> writes:
>> I'm slightly worried though since that seems to have changed from 8.2,
>> which I oprofiled over Christmas.
>
> If you were testing a case with wider rows than Heikki tested, you'd see
> less impact --- the cost of the old way was O(N^2) in the number of
> tuples that fit on a page, so the behavior gets rapidly worse as you get
> down to smaller tuple sizes.  (Come to think of it, the cmin/cmax
> collapse would be a factor here too.)

Or larger block sizes of course. A 32kb block would be 16x as bad which starts
to be pretty serious.

--
  Gregory Stark
  EnterpriseDB          http://www.enterprisedb.com