Re: On disable_cost

From: Andres Freund <andres(at)anarazel(dot)de>
To: Thomas Munro <thomas(dot)munro(at)gmail(dot)com>
Cc: Zhenghua Lyu <zlv(at)pivotal(dot)io>, PostgreSQL Hackers <pgsql-hackers(at)lists(dot)postgresql(dot)org>
Subject: Re: On disable_cost
Date: 2019-11-01 16:00:38
Message-ID: 20191101160038.wn3qkvp4psnatmm3@alap3.anarazel.de
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Hi,

On 2019-11-01 19:58:04 +1300, Thomas Munro wrote:
> On Fri, Nov 1, 2019 at 7:42 PM Zhenghua Lyu <zlv(at)pivotal(dot)io> wrote:
> > It is tricky to set disable_cost a huge number. Can we come up with better solution?
>
> What happens if you use DBL_MAX?

That seems like a bad idea - we add the cost multiple times. And we
still want to compare plans that potentially involve that cost, if
there's no other way to plan the query.

- Andres

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