Re: libpq Alternate Row Processor

On 2/8/17 5:11 PM, Kyle Gearhart wrote:
> Overall, wall clock improves 24%. User time elapsed is a 430% improvement. About half the time is spent waiting on the IO with the callback. With the regular pqRowProcessor only about 16% of the time is spent waiting on IO.

To wit...

real user sys
single row 0.214 0.131 0.048
callback 0.161 0.030 0.051

Those are averaged over 11 runs.

Can you run a trace to see where all the time is going in the single row
case? I don't see an obvious time-suck with a quick look through the
code. It'd be interesting to see how things change if you eliminate the
filler column from the SELECT.

Also, the backend should be buffering ~8kb of data before handing that
to the socket. If that's more than the kernel can buffer I'd expect a
serious performance hit.
--
Jim Nasby, Data Architect, Blue Treble Consulting, Austin TX
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