Re: [WIP] speeding up GIN build with parallel workers - Mailing list pgsql-hackers

From Peter Geoghegan
Subject Re: [WIP] speeding up GIN build with parallel workers
Date
Msg-id CAM3SWZQ2yvbxmEk0ZmXVAV8jjOe_e_bi6_zD24_QbSPgyFVEeQ@mail.gmail.com
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In response to Re: [WIP] speeding up GIN build with parallel workers  ("Constantin S. Pan" <kvapen@gmail.com>)
Responses Re: [WIP] speeding up GIN build with parallel workers
List pgsql-hackers
On Wed, Mar 16, 2016 at 2:25 AM, Constantin S. Pan <kvapen@gmail.com> wrote:
> The backend just waits for the results from the workers and merges them
> (in case wnum > 0). So the 1-worker configuration should never be used,
> because it is as sequential as the 0-worker, but adds data transfer.

This is why I wanted an easy way of atomically guaranteeing some
number of workers (typically 2), or not using parallelism at all. I
think the parallel worker API should offer a simple way to do that in
cases like this, where having only 1 worker is never going to win.

-- 
Peter Geoghegan



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