Does priority = 'Background' turn off intra-query parallelism?

Breck_Carter — Sun, 07 Oct 2018 15:00:36 GMT

The Watcom Rule would imply "Intra-query parallelism is not used for connections with priority set to Background"... is that true?

The Help for the old background_priority option [deprecated] says "Intra-query parallelism is not used for connections with background_priority set to On".

However, the Help for the new priority option makes no such claim for SET TEMPORARY OPTION priority = 'Background'.

Re: Does priority = 'Background' turn off intra-query parallelism?

VolkerBarth — Mon, 15 Oct 2018 08:02:04 GMT

I have justed noted that the docs do tell about that, I have not checked reality:)

From the v17 "Parallelism in queries" topic:

Following is a list of circumstances in which a query cannot take advantage of parallelism, either at optimization or execution time:
* the server computer does not have multiple processors
* [...]
* the priority option is set to background

Makes sense, particularly as the deprecated Background_priority option is implemented as setting the priority option to 'Background'...

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Does priority = 'Background' turn off intra-query parallelism?

Re: Does priority = 'Background' turn off intra-query parallelism?