Re: Rename max_parallel_degree?

On Fri, Sep 16, 2016 at 11:54 PM, Robert Haas <robertmhaas@gmail.com> wrote:
>
> +       /*
> +        * We need a write barrier to make sure the update of
> +        * parallel_terminate_count is done before the store to in_use
> +        */
>
> Does the order actually matter here?
>

I think so.  If slot->in_use is reordered before the check of
is_parallel_worker, then it is possible that concurrent registration
of worker can mark the is_parallel_worker as false before we check the
flag here.  See explanation in previous e-mail [1].


[1] - https://www.postgresql.org/message-id/CAA4eK1%2BQ_DdJ28qXYSHZiBKNf2MY1QFrv5XAOAw4ZXHw4TPMxA%40mail.gmail.com

-- 
With Regards,
Amit Kapila.
EnterpriseDB: http://www.enterprisedb.com