Re: Fixed xloginsert_locks for 9.4

On 10/3/14, 8:26 AM, Andres Freund wrote:
> #define NUM_XLOGINSERT_LOCKS 1
> tps = 52.711939 (including connections establishing)
> #define NUM_XLOGINSERT_LOCKS 8
> tps = 286.496054 (including connections establishing)
> #define NUM_XLOGINSERT_LOCKS 16
> tps = 346.113313 (including connections establishing)
> #define NUM_XLOGINSERT_LOCKS 24
> tps = 363.242111 (including connections establishing)

Just to clarify: that 10% number I threw out was meant as a rough
estimate for a system with the default configuration, which is all that
I tested. It seemed like people would likely need to tune all the usual
things like checkpoint_segments, shared_buffers, etc. as well before
seeing much better. You did all that, and sure enough the gain went up;
thanks for confirming my guess.

I still don't think that means this needs a GUC for 9.4. Look at that
jump from 1 to 8. The low-hanging fruit here hasn't just been knocked
off. It's been blended into a frozen drink, poured into a glass, and
had a little paper umbrella put on top. I think that's enough for 9.4.
But, yes, let's see if we can add delivery to the side of the pool in
the next version too.

--
Greg Smith greg(dot)smith(at)crunchydatasolutions(dot)com
Chief PostgreSQL Evangelist - http://crunchydatasolutions.com/