Postgres Pro
Downloads
Home   >   mailing lists

Re: Parallel tuplesort (for parallel B-Tree index creation) - Mailing list pgsql-hackers

From Peter Geoghegan
Subject Re: Parallel tuplesort (for parallel B-Tree index creation)
Date
Msg-id CAM3SWZSxvacUK8o22Jk0ufSUqW-nVPaBYcLnrse_hMHFbYN84g@mail.gmail.com
Whole thread Raw
In response to Re: Parallel tuplesort (for parallel B-Tree index creation)  (Robert Haas <robertmhaas@gmail.com>)
Responses Re: Parallel tuplesort (for parallel B-Tree index creation)
List pgsql-hackers
Tree view 
On Mon, Sep 26, 2016 at 6:58 PM, Robert Haas <robertmhaas@gmail.com> wrote:
>> That requires some kind of mutual exclusion mechanism, like an LWLock.
>
> No, it doesn't.  Shared memory queues are single-reader, single-writer.

The point is that there is a natural dependency when merging is
performed eagerly within the leader. One thing needs to be in lockstep
with the others. That's all.


-- 
Peter Geoghegan

pgsql-hackers by date:

Previous
From: Tom Lane
Date:
Subject: Re: [GENERAL] inconsistent behaviour of set-returning functions in sub-query with random()
Next
From: Stephen Frost
Date:
Subject: Re: Remove superuser() checks from pgstattuple