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.smith@crunchydatasolutions.com
Chief PostgreSQL Evangelist - http://crunchydatasolutions.com/