Re: BUG #14393: Querry plan creation time is too long

Hi, Jeff!
Thank you for your response! Here is some additional information regarding
my first question. The querry itself and two plans(1:,2:)

2016-10-25 0:11 GMT+05:00 Jeff Janes <jeff(dot)janes(at)gmail(dot)com>:

> On Mon, Oct 24, 2016 at 6:04 AM, <ufaowl(at)gmail(dot)com> wrote:
>
>> The following bug has been logged on the website:
>>
>> Bug reference: 14393
>> Logged by: Vadim Akbashev
>> Email address: ufaowl(at)gmail(dot)com
>> PostgreSQL version: 9.5.4
>> Operating system: Centos 6.8
>> Description:
>>
>> Hello!
>> I have two questions concerning choosing\creation time of querry plan
>> regaring default_statistic_target parameter. I noticed that querry plan
>> creation time increases when default_statistic_target is more than 1000.
>> It
>> reaches 14 sec for database without any load when
>> default_statistic_target =
>> 10 000.
>> I wonder:
>> 1) Is such behavior considered normal? If it is, where I can get
>> documentation regulating this?
>>
>
> It is normal that increasing default_statistic_target will increase
> planning time. Increasing it to 14 seconds is undesirable, of course, but
> without seeing the query it is hard to say more than that. This could be a
> bug which leads to pathologically slow planning in some cases, or it could
> be that your query is just a monster query that is difficult to plan.
>
>
> 2) Is there any way to limit querry plan creation time?
>>
>
> See the *_collapse_limit settings here, https://www.postgresql.org/
> docs/9.5/static/runtime-config-query.html
>
> And see the further sections referred to from there.
>
> Cheers,
>
> Jeff
>