contrib/pg_stat_statements 1226

Here is an updated version of contrib/pg_stat_statements patch.

"Alex Hunsaker" <badalex@gmail.com> wrote:

> >> I think the explain_analyze_format guc is a clever way of getting
> >> around the explain analyze verbose you proposed earlier.  But I dont
> >> see any doc updates for it.

Documentation is added.

> How about just pg_stat_statements.track ?

I renamed the variables to:
    - pg_stat_statements.limit
    - pg_stat_statements.track
    - pg_stat_statements.saved_file

I also modified assign_custom_variable_classes()
to accept '_' as a prefix character, not only 0-9A-Za-z.

> I do like the consistency of having the custom gucs be the same as the
> module name, easy to grep or google for.

Should I also rename variables used in auto_explain module?
It uses 'explain.*' now.

Regards,
---
ITAGAKI Takahiro
NTT Open Source Software Center