Re: Apply the "LIMIT 1" optimization to partial DISTINCT - Mailing list pgsql-hackers

From Richard Guo
Subject Re: Apply the "LIMIT 1" optimization to partial DISTINCT
Date
Msg-id CAMbWs49VLFhWcx7i2L2XPypDD=BmTiPZvYe+SxAvyg+gVGQ4wQ@mail.gmail.com
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In response to Re: Apply the "LIMIT 1" optimization to partial DISTINCT  (David Rowley <dgrowleyml@gmail.com>)
List pgsql-hackers

On Wed, Jan 31, 2024 at 12:26 PM David Rowley <dgrowleyml@gmail.com> wrote:
On Fri, 26 Jan 2024 at 21:14, David Rowley <dgrowleyml@gmail.com> wrote:
> However, having said that. Parallel plans are often picked when there
> is some highly selective qual as parallel_tuple_cost has to be applied
> to fewer tuples for such plans, so probably this is worth doing.

I was messing around with your test case and didn't manage to get any
plan that had any rows to use the partial path with the LIMIT.  I
ended up dropping the test that was checking the results were empty as
I didn't think it added much more value over the EXPLAIN output.

I pushed the result.

Thanks for pushing it!

Thanks
Richard

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