Yeah the grammar ":variable" is used to set a parameter, the user will feel disorientated if there is no support. The attached patch supports this new case, based on Itagaki-san's last version. I also added a warning to tell the user that pgbench is slowing down when using this feature.
If nobody is against it, I will mark it as ready to commit.
-- Regards,
Michael Paquier NIPPON TELEGRAPH AND TELEPHONE CORPORATION NTT Open Source Software Center