Re: Explain analyze getrusage tracking

On Tue, Nov 16, 2010 at 2:53 PM, Greg Stark <stark(at)mit(dot)edu> wrote:
>> Yeah, VERBOSE is kind of a catch-all for things that we don't have
>> individual flags for.  But I think it's better for each piece of data
>> to depend on one setting, rather than a combination of two or more
>> settings.  Otherwise you end up being forced to use VERBOSE and then
>> you get this deluge of output.  I'd actually sort of like to remove
>> some things from VERBOSE and give them their own settings, rather than
>> adding more.  The fact that VERBOSE turns on "Output:" is particularly
>> annoying.
>
> I tend to think it's "don't be clever about showing me just the useful
> stuff, include whatever you've got even if you think it's not useful".
> I would consider it a bug if there's anything that requires VERBOSE
> and a user finds is relevant to a fixing a user problem (as opposed to
> debugging a postgres bug).
>
> I'm concerned about the converse problem. The "I why do I have to
> include two dozen flags to get postgres to actually include
> everything?". Along with the "try turning on this flag and resending
> the plan. Hm, oops forgot a flag resend it again with this too. Oh
> that's still not including something we need try it a third time with
> this flag" etc.

Well, the reason's pretty obvious in this case: each of ANALYZE,
BUFFERS, and RESOURCE adds a huge amount of incremental overhead. I
wouldn't object to having a flag that says "just turn on absolutely
everything you've got". Then you could just say:

EXPLAIN (THECRAPOUTOFIT) query...

In any case, this seems like an argument for making RESOURCE print
everything we think might ever be useful, rather than just some subset
of it. A rule that says "print some of the RESOURCE information when
RESOURCE is specified but the rest only if VERBOSE is also specified
or if a non-text output format is used" seems to have exactly the sort
of ickiness you're complaining about; I'd rather make it all or
nothing.

--
Robert Haas
EnterpriseDB: http://www.enterprisedb.com
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