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
