Re: EXPLAIN BUFFERS

On Thu, Dec 10, 2009 at 10:50 AM, Tom Lane <tgl@sss.pgh.pa.us> wrote:
> Robert Haas <robertmhaas@gmail.com> writes:
>> On Thu, Dec 10, 2009 at 9:03 AM, Euler Taveira de Oliveira
>> <euler@timbira.com> wrote:
>>> Why? If you want this information for all of your queries, you can always set
>>> auto_explain.log_min_duration to 0. But if you're suggesting that we should
>>> maintain log_statement_stats (that was not I understand from Tom's email [1]),
>>> it's not that difficult to a change ShowBufferUsage().
>
>> Mmm, OK, if Tom thinks we should rip it out, I'm not going to second-guess him.
>
> Feel free to question that.  But it's ancient code and I'm not convinced
> it still has a reason to live.  If you want to investigate the I/O
> behavior of a particular query, you'll use EXPLAIN.  If you want to get
> an idea of the system-wide behavior, you'll use the stats collector.
> What use case is left for the backend-local counters?

Beats me.  Tracing just your session without having to EXPLAIN each
query (and therefore not get the output rows)?  OK, I'm reaching.  I
tend to be very conservative about ripping things out that someone
might want unless they're actually getting in the way of doing some
new thing that we want to do - but so are you, and you know the
history of this code better than I do.  I'm happy to save my
questioning for a more important issue.

...Robert