Re: PATCH: use foreign keys to improve join estimates v1

From: Tomas Vondra <tomas(dot)vondra(at)2ndquadrant(dot)com>
To: Simon Riggs <simon(at)2ndQuadrant(dot)com>
Cc: Amit Langote <Langote_Amit_f8(at)lab(dot)ntt(dot)co(dot)jp>, David Steele <david(at)pgmasters(dot)net>, David Rowley <david(dot)rowley(at)2ndquadrant(dot)com>, PostgreSQL-development <pgsql-hackers(at)postgresql(dot)org>
Subject: Re: PATCH: use foreign keys to improve join estimates v1
Date: 2016-04-07 12:35:39
Message-ID: 126fbff3-cdd7-2d0d-7d5e-a61598da1ea6@2ndquadrant.com
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Hi,

On 04/07/2016 01:23 PM, Simon Riggs wrote:
> On 7 April 2016 at 00:15, Tomas Vondra <tomas(dot)vondra(at)2ndquadrant(dot)com
> <mailto:tomas(dot)vondra(at)2ndquadrant(dot)com>> wrote:
>
>
> Right. Fixed.
>
>
> 0001 committed. I added comments and a fastpath when no triggers are
> present.
>
>
> For 0002, I would be more comfortable adding
> enable_fk_plans = on (true) | off
>
> even if we decided to remove that parameter that before release.

Attached is 0002 with the GUC added. I certainly believe we should think
twice before keeping the GUC in the final release - it's definitely
useful for testing etc. but I'm afraid it'd be just another tuning knob
for regular users.

regards

--
Tomas Vondra http://www.2ndQuadrant.com
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services

Attachment Content-Type Size
0002-use-fkeys-in-join-estimation.patch binary/octet-stream 13.8 KB

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