I add exponential distribution random generator (and little bit
refactoring:) ).
I use inverse transform method to create its distribution. It's very
simple method that is
created by - log (rand()). We can control slope of distribution using
threshold parameter.
It is same as gaussian threshold.
usage example
pgbench --exponential=NUM -S
Attached graph is created with exponential threshold = 5. We can see
exponential
distribution in the graphs. It supports -S, -N options and custom script.
So we set
"¥setexponential [var] [min] [max] [threshold]" in a transaction pattern
file,
it appear distribution we want.
We have no time to fix its very much... But I think almost part of patch
have been completed.
Regards,
--
Mitsumasa KONDO
NTT Open Source Software Center
