Re: [HACKERS] Parallel Append implementation - Mailing list pgsql-hackers

From Amit Khandekar
Subject Re: [HACKERS] Parallel Append implementation
Date
Msg-id CAJ3gD9dwMi49pQ2vSAVjvW1zpBJmovDnmg9MZNiKR7X9s15h-A@mail.gmail.com
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In response to Re: [HACKERS] Parallel Append implementation  (Ashutosh Bapat <ashutosh.bapat@enterprisedb.com>)
List pgsql-hackers
On 10 March 2017 at 14:05, Ashutosh Bapat
<ashutosh.bapat@enterprisedb.com> wrote:
>> The need for
>> num_workers=-1 will still be there for partial plans, because we need
>> to set it to -1 once a worker finishes a plan.
>>
>
> IIRC, we do that so that no other workers are assigned to it when
> scanning the array of plans. But with the new scheme we don't need to
> scan the non-parallel plans for when assigning plan to workers so -1
> may not be needed. I may be wrong though.
>

Still, when a worker finishes a partial subplan , it marks it as -1,
so that no new workers pick this, even if there are other workers
already executing it.

-- 
Thanks,
-Amit Khandekar
EnterpriseDB Corporation
The Postgres Database Company



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