Re: Should we add GUCs to allow partition pruning to be disabled? - Mailing list pgsql-hackers

From Alvaro Herrera
Subject Re: Should we add GUCs to allow partition pruning to be disabled?
Date
Msg-id 20180510021724.2k5csd7z6pkfot7q@alvherre.pgsql
Whole thread Raw
In response to Re: Should we add GUCs to allow partition pruning to be disabled?  (David Rowley <david.rowley@2ndquadrant.com>)
List pgsql-hackers
David Rowley wrote:
> On 10 May 2018 at 14:01, Alvaro Herrera <alvherre@2ndquadrant.com> wrote:
> > I'm thinking something a bit more radical.  First, since partition
> > pruning is the future and constraint exclusion is soon to be a thing of
> > the past, we should describe pruning first, and then describe exclusion
> > in terms of pruning.
> 
> But... that's not true.  The chapter describes inheritance partitioned
> tables too, and we're not getting rid of constraint exclusion because
> it's needed for those.

Oh, I'm sure it is, but nobody is going to set up new inheritance
partitioned tables anymore, except people who pg_upgrade from older
releases.  (And while I haven't tried, I'm sure it's possible to migrate
from old-style to new-style partitioned tables without incurring full
table rewrites, with little downside and lots to gain.)

Now, maybe you argue that we could have a structure like this instead:

5.10.1. Overview
5.10.2. Declarative Partitioning
5.10.3. Partition Pruning
5.10.4. Implementation Using Inheritance
5.10.5. Constraint Exclusion

I wouldn't oppose that.

> However, that might not mean your patch has to be changed. I'd better
> have a look...

Thanks :-)

-- 
Álvaro Herrera                https://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services


pgsql-hackers by date:

Previous
From: David Rowley
Date:
Subject: Re: Should we add GUCs to allow partition pruning to be disabled?
Next
From: Amit Langote
Date:
Subject: Re: Indexes on partitioned tables and foreign partitions