Re: pgbench stats per script & other stuff

> I liked @ because it makes sense to read it as the word "at".

Yep, why not.

>> Prepending classic to the names does not look necessary. I would 
>> suggest "tpcb-like", "simple-update" & "select-only", or even maybe any 
>> prefix. If the bench scripts could be read from some pg directory 
>> instead of being actually inlined, even more code could be dropped from 
>> pgbench.
>
> I think including classic would be a very good idea.

Hmm. This is the command line, you have to type them! With a prefix-based
approach this suggests that the builtin names must start differently so as 
to be easily selected.

> We might want to add a TPC-C like workload in the future, or any number 
> of other things.  Naming things in a good way from the outset can only 
> make that easier.

Here is a v4 which:

  - removes -w stuff

  - enhance -f with @weight

  - adds -b/--builtin name@weight, based on prefix

    builtin names are: tpcb-like, simple-update & select-only,
    which matches their more or less historical names
    (although I wasn't sure of "tpcb-sort-of", so I put "tpcb-like")

  - removes -B (now can be accessed with -b tpcb-like)

Pgbench builtin scripts are still inlined in the code, not in a separate 
directory, which might be an option to simplify the code and allow easy 
extensions.

I still think that the "--per-script-stats" option is useless and per 
script stats should always be on as soon as several scripts are running.

Even more, I think that stats (maybe no per-command stat though) should
always be collected. The point of pgbench is to collect data, and the
basic end-of-run tps summary is very terse and does not reflect much
of what happened during the run.

Also, maybe per-command detailed stats should use the same common struct 
to hold data as all other stats. I did not change it because it is 
maintained in a different part of the code.

-- 
Fabien.