Re: Parallel Append implementation

From: Amit Khandekar <amitdkhan(dot)pg(at)gmail(dot)com>
To: Robert Haas <robertmhaas(at)gmail(dot)com>
Cc: Ashutosh Bapat <ashutosh(dot)bapat(at)enterprisedb(dot)com>, pgsql-hackers <pgsql-hackers(at)postgresql(dot)org>
Subject: Re: Parallel Append implementation
Date: 2017-02-15 09:43:28
Message-ID: CAJ3gD9ctD=heQAzj4nJSuv7aKhiCt4+q_p+7pM3jQW+bvwksxw@mail.gmail.com
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> On 14 February 2017 at 22:35, Robert Haas <robertmhaas(at)gmail(dot)com> wrote:
>> For example, suppose that I have a scan of two children, one
>> of which has parallel_workers of 4, and the other of which has
>> parallel_workers of 3. If I pick parallel_workers of 7 for the
>> Parallel Append, that's probably too high.

In the patch, in such case, 7 workers are indeed selected for Parallel
Append path, so that both the subplans are able to execute in parallel
with their full worker capacity. Are you suggesting that we should not
?

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