Re: condition variables - Mailing list pgsql-hackers

From Peter Geoghegan
Subject Re: condition variables
Date
Msg-id CAM3SWZTLOfWUGKxbd1xh1UVVMBVaFLExEOSGZOHBfiBrSiWODw@mail.gmail.com
Whole thread Raw
In response to condition variables  (Robert Haas <robertmhaas@gmail.com>)
Responses Re: condition variables  (Robert Haas <robertmhaas@gmail.com>)
List pgsql-hackers
On Thu, Aug 11, 2016 at 2:47 PM, Robert Haas <robertmhaas@gmail.com> wrote:
> Another approach to the problem is to use a latch wait loop.  That
> almost works.  Interrupts can be serviced, and you can recheck shared
> memory to see whether the condition for proceeding is satisfied after
> each iteration of the loop.  There's only one problem: when you do
> something that might cause the condition to be satisfied for other
> waiting backends, you need to set their latch - but you don't have an
> easy way to know exactly which processes are waiting, so how do you
> call SetLatch?  I originally thought of adding a function like
> SetAllLatches(ParallelContext *) and maybe that can work, but then I
> had what I think is a better idea, which is to introduce a notion of
> condition variables.

I don't see a CF entry for this. Are you planning to work on this
again soon, Robert?

I have an eye on this patch due to my work on parallel CREATE INDEX.
It would be nice to have some rough idea of when you intend to commit
this.

-- 
Peter Geoghegan



pgsql-hackers by date:

Previous
From: Amit Langote
Date:
Subject: Comment typo in execIndexing.c
Next
From: Pavan Deolasee
Date:
Subject: Re: Vacuum: allow usage of more than 1GB of work mem