Re: Rename max_parallel_degree?

On 23/09/2016 21:10, Robert Haas wrote:
> On Fri, Sep 23, 2016 at 8:54 AM, Peter Eisentraut
> <peter.eisentraut@2ndquadrant.com> wrote:
>> On 9/20/16 4:07 PM, Robert Haas wrote:
>>> No, I'm assuming that the classes would be built-in.  A string tag
>>> seems like over-engineering to me, particularly because the postmaster
>>> needs to switch on the tag, and we need to be very careful about the
>>> degree to which the postmaster trusts the contents of shared memory.
>>
>> I'm hoping that we can come up with something that extensions can
>> participate in, without the core having to know ahead of time what those
>> extensions are or how they would be categorized.
>>
>> My vision is something like
>>
>> max_processes = 512  # requires restart
>>
>> process_allowances = 'connection:300 superuser:10 autovacuum:10
>> parallel:30 replication:10 someextension:20 someotherextension:20'
>> # does not require restart
> 
> I don't think it's going to be very practical to allow extensions to
> participate in the mechanism because there have to be a finite number
> of slots that is known at the time we create the main shared memory
> segment.
> 
> Also, it's really important that we don't add lots more surface area
> for the postmaster to crash and burn.
> 

It seems that there's no objection on Robert's initial proposal, so I'll
try to implement it.

I've already fixed every other issues mentioned upthread, but I'm facing
a problem for this one.  Assuming that the bgworker classes are supposed
to be mutually exclusive, I don't see a simple and clean way to add such
a check in SanityCheckBackgroundWorker().  Am I missing something
obvious, or can someone give me some advice for this?

-- 
Julien Rouhaud
http://dalibo.com - http://dalibo.org