Re: [PATCH] explain tup_fetched/returned in monitoring-stats

On 20 October 2012 07:43, Abhijit Menon-Sen <ams@2ndquadrant.com> wrote:
> At 2012-10-15 10:28:17 -0400, robertmhaas@gmail.com wrote:
>>
>> > Is there any concise description that applies? […]
>>
>> I don't think there is.  I think we need to replace those counters
>> with something better.  The status quo is quite bizarre.
>
> Fair enough. Do you have any ideas?
>
> I see two possibilities: first, they could become the tuple analogue of
> blks_read and blks_hit, i.e. tuples fetched from disk, and tuples found
> in memory. (I don't know if there's a simple way to count that, and I'm
> not sure it would be very useful; we have blks_{read,hit} after all.)
>
> Second, it could do what I thought it did, which is count tuples fetched
> by sequential and index scans respectively. I'm not sure how useful the
> values would be, but at least it's information you can't get elsewhere.

We already have the second one on pg_stat_all_tables.

A third possibility exists, which is the one Tom described above.

Collecting information at pg_stat_database level isn't interesting
anyway (to me) for information that can be collected at table level.

-- Simon Riggs                   http://www.2ndQuadrant.com/PostgreSQL Development, 24x7 Support, Training & Services