Re: Experimental evaluation of PostgreSQL's query optimizer

On 24 December 2015 at 03:43, Jim Nasby <Jim(dot)Nasby(at)bluetreble(dot)com> wrote:

> On 12/21/15 7:49 PM, Craig Ringer wrote:
>
>> CREATE JOIN STATISTICS ON t1 JOIN t2 USING (somecol);
>>
>>
>> That way we let an admin who's tuning queries direct effort at problem
>> areas. It's not automagical, but it's an area where tools could analyze
>> pg_stat_statements to direct effort, much like is currently done for
>> index creation. Like index creation I don't think it's practical to do
>> this entirely automatically and behind the scenes since collecting the
>> stats for all possibilities rapidly gets prohibitive.
>>
>
> There's an extremely common case that could (and IMO should) be automated
> though, which is computing these statistics for all foreign keys. We can
> have a way to disable that for specific keys if necessary, but I'd bet it's
> extremely rare to have a FK that you never join on.
>

Good point.

--
Craig Ringer http://www.2ndQuadrant.com/
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