Re: RFC: replace pg_stat_activity.waiting with something more descriptive - Mailing list pgsql-hackers

From Robert Haas
Subject Re: RFC: replace pg_stat_activity.waiting with something more descriptive
Date
Msg-id CA+TgmobET4H3aJ1qQfLPy0fU9rTBTQCmUVEbHaokzPP_U_==mQ@mail.gmail.com
Whole thread Raw
In response to Re: RFC: replace pg_stat_activity.waiting with something more descriptive  (Heikki Linnakangas <hlinnaka@iki.fi>)
Responses Re: RFC: replace pg_stat_activity.waiting with something more descriptive  (Ildus Kurbangaliev <i.kurbangaliev@postgrespro.ru>)
Re: RFC: replace pg_stat_activity.waiting with something more descriptive  (Heikki Linnakangas <hlinnaka@iki.fi>)
Re: RFC: replace pg_stat_activity.waiting with something more descriptive  (Amit Kapila <amit.kapila16@gmail.com>)
List pgsql-hackers
On Tue, Jul 28, 2015 at 3:28 PM, Heikki Linnakangas <hlinnaka@iki.fi> wrote:
> * The patch requires that the LWLOCK_INDIVIDUAL_NAMES array is kept in sync
> with the list of individual locks in lwlock.h. Sooner or later someone will
> add an LWLock and forget to update the names-array. That needs to be made
> less error-prone, so that the names are maintained in the same place as the
> #defines. Perhaps something like rmgrlist.h.

This is a good idea, but it's not easy to do in the style of
rmgrlist.h, because I don't believe there's any way to define a macro
that expands to a preprocessor directive.  Attached is a patch that
instead generates the list of macros from a text file, and also
generates an array inside lwlock.c with the lock names that gets used
by the Trace_lwlocks stuff where applicable.

Any objections to this solution to the problem?  If not, I'd like to
go ahead and push this much.  I can't test the Windows changes
locally, though, so it would be helpful if someone could check that
out.

> * Instead of having LWLOCK_INDIVIDUAL_NAMES to name "individual" locks, how
> about just giving each one of them a separate tranche?

I don't think it's good to split things up to that degree;
standardizing on one name per fixed lwlock and one per tranche
otherwise seems like a good compromise to me.

--
Robert Haas
EnterpriseDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company

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