Re: [HACKERS] SERIALIZABLE with parallel query - Mailing list pgsql-hackers

From Robert Haas
Subject Re: [HACKERS] SERIALIZABLE with parallel query
Date
Msg-id CA+Tgmoa43ct2d-JHhexdqrTQ=+w5cZ0=9JL15mjAtAwOVc0sPw@mail.gmail.com
Whole thread Raw
In response to SERIALIZABLE with parallel query  (Thomas Munro <thomas.munro@enterprisedb.com>)
Responses Re: [HACKERS] SERIALIZABLE with parallel query  (Thomas Munro <thomas.munro@enterprisedb.com>)
List pgsql-hackers
On Tue, Nov 8, 2016 at 4:51 PM, Thomas Munro
<thomas.munro@enterprisedb.com> wrote:
> Currently we don't generate parallel plans in SERIALIZABLE.  What
> problems need to be solved to be able to do that?  I'm probably
> steamrolling over a ton of subtleties and assumptions here, but it
> occurred to me that a first step might be something like this:
>
> 1.  Hand the leader's SERIALIZABLEXACT to workers.
> 2.  Make sure that workers don't release predicate locks.
> 3.  Make sure that the leader doesn't release predicate locks until
> after the workers have finished accessing the leader's
> SERIALIZABLEXACT.  I think this is already the case.

What happens if the workers exit at the end of the query and the
leader then goes on and executes more queries?  Will the
worker-acquired predicate locks be retained or will they go away when
the leader exits?

-- 
Robert Haas
EnterpriseDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company



pgsql-hackers by date:

Previous
From: Robert Haas
Date:
Subject: Re: [HACKERS] CREATE TABLE with parallel workers, 10.0?
Next
From: Kuntal Ghosh
Date:
Subject: Re: [HACKERS] exposing wait events for non-backends (was: Trackingwait event for latches)