Re: Parallel hints in PostgreSQL with consistent perfromance

On Thursday, December 28, 2023, mohini mane <mohini(dot)android(at)gmail(dot)com>
wrote:

> Thank you for your response !!
> I am experimenting with SQL query performance for SELECT queries on large
> tables and I observed that changing/increasing the degree of parallel hint
> doesn't give the expected performance improvement.
>
> I have executed the SELECT query with 2,4 & 6 parallel degree however
> every time only 4 workers launched & there was a slight increase in
> Execution time as well, why there is an increase in execution time with
> parallel degree 6 as compared to 2 or 4?
>

Random environmental effects.

Also, analyzing a performance test without understanding how “buffers” are
used is largely pointless.

Whatever told you about that comment syntax is hallucinating.

Please don’t reply by top-posting. Inline reply to the comments others make
directly and trim as needed. Simply restating your first email isn’t
productive.

You cannot enforce the number of workers used, only the the maximum. That
is you knob.

David J.