Re: Slowness of extended protocol

On 2016-07-31 22:26:00 +0100, Greg Stark wrote:
> I think you're looking at this the wrong way around. 30% of what?
> You're doing these simple read-only selects on a database that
> obviously is entirely in RAM. If you do the math on the numbers you
> gave above the simple protocol took 678 microseconds per transaction
> and the extended protocol took 876 microseconds. The difference is 198
> microseconds. I'm not sure exactly where those 200us are going and
> perhaps it could be lower but in what real-world query is it going to
> have a measurable impact on the total time?

FWIW, I've observed the same with (a bit) more complicated queries. A
part of this is that the extended protocol simply does
more. PQsendQueryGuts() sends Parse/Bind/Describe/Execute/Sync - that's
simply more work and data over the wire than a single Q message.

Whether that matters for a given workload or not, is a different
question, but I think it's pretty clear that it can for some.

Shay, are you using unnamed or named portals? There's already a shortcut
path for the former in some places.

Greetings,

Andres Freund