pgbench: Skipping the creating primary keys after initialization

Hi all,

I'd like to propose a new option -I for pgbench command which skips
the creating primary keys after initialized tables. This option is
useful for users who want to do bench marking with no index or indexes
other than btree primary index. If we initialize pgbench tables at a
large number scale factor the primary key index creation takes a long
time even if we're going to use other types of indexes. With this
option, the initialization time is reduced and you can create indexes
as you want.

Feedback is very welcome. I'll add this patch to the next CF.

Regards,

--
Masahiko Sawada
NIPPON TELEGRAPH AND TELEPHONE CORPORATION
NTT Open Source Software Center