On Wed, Mar 16, 2016 at 1:23 PM, Julien Rouhaud
<julien.rouhaud@dalibo.com> wrote:
> On 16/03/2016 17:55, Robert Haas wrote:
>> On Wed, Mar 16, 2016 at 12:47 PM, Julien Rouhaud
>> <julien.rouhaud@dalibo.com> wrote:
>>> Something like a "min_parallel_degree" then ?
>>
>> Why not just parallel_degree without any prefix? As in, when scanning
>> this table in parallel, the reloption suggests using N workers.
>>
>
> Agreed.
>
> PFA v2 that implements that.
I think create_parallel_paths shouldn't actually run the loop if the
reloption is specified; it should just adopt the specified value (or
max_parallel_degree, whichever is less). Right now, you have it doing
the work to compute the default value but then overriding it.
Also, I think parallel_degree should be down in the section that says
/* information about a base rel (not set for join rels!) */ and I
think it should be called something like rel_parallel_degree, to make
it more clear that it's a value set on the relation level.
Let's leave out the parallel_threshold stuff for now.
--
Robert Haas
EnterpriseDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company
