Re: slight tweaks to documentation about runtime pruning

From: Amit Langote <Langote_Amit_f8(at)lab(dot)ntt(dot)co(dot)jp>
To: Amit Langote <amitlangote09(at)gmail(dot)com>, David Rowley <david(dot)rowley(at)2ndquadrant(dot)com>
Cc: PostgreSQL-development <pgsql-hackers(at)postgresql(dot)org>
Subject: Re: slight tweaks to documentation about runtime pruning
Date: 2018-12-14 02:52:03
Message-ID: 304131bd-e1a5-8cb1-25b6-5b567463fde2@lab.ntt.co.jp
Views: Raw Message | Whole Thread | Download mbox | Resend email
Thread:
Lists: pgsql-hackers

On 2018/12/10 0:57, Amit Langote wrote:
> On Sun, Dec 9, 2018 at 8:13 PM David Rowley
> <david(dot)rowley(at)2ndquadrant(dot)com> wrote:
>> listp1 was scanned twice (loops=2), listp2 was scanned just once.
>>
>> Now it is true that if the subplan was executed 0 times that it will
>> appear as "(never executed)", but do we really need to explain in this
>> area that "(never executed)" means loops=0?
>
> Ah, I see what you mean. So, "(never executed)" is not the only sign
> of of run-time pruning occurring. The value of loops can be different
> for different subplans / partitions, and it being lower for a given
> subplan means that the subplan has been pruned more number of times.

I updated the patch. Regarding whether we should mention "(never
executed)", it wouldn't hurt to mention it imho, exactly because it's
shown in the place of showing loops=0. How about the attached?

Thanks,
Amit

Attachment Content-Type Size
runtime-pruning-doc-tweak-v2.patch text/plain 1.0 KB

In response to

Responses

Browse pgsql-hackers by date

  From Date Subject
Next Message Thomas Munro 2018-12-14 02:52:23 Re: Valgrind failures in Apply Launcher's bgworker_quickdie() exit
Previous Message Andres Freund 2018-12-14 02:15:19 Re: Valgrind failures in Apply Launcher's bgworker_quickdie() exit