Re: Add estimated hit ratio to Memoize in EXPLAIN to explain cost adjustment

From: Ilia Evdokimov <ilya(dot)evdokimov(at)tantorlabs(dot)com>
To: David Rowley <dgrowleyml(at)gmail(dot)com>, Robert Haas <robertmhaas(at)gmail(dot)com>
Cc: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>, Lukas Fittl <lukas(at)fittl(dot)com>, Daniel Gustafsson <daniel(at)yesql(dot)se>, PostgreSQL Hackers <pgsql-hackers(at)lists(dot)postgresql(dot)org>, Nikolay Samokhvalov <samokhvalov(at)gmail(dot)com>, Andrei Lepikhov <lepihov(at)gmail(dot)com>
Subject: Re: Add estimated hit ratio to Memoize in EXPLAIN to explain cost adjustment
Date: 2025-04-14 23:14:37
Message-ID: 3ea66a50-e4b0-4f20-ae0c-4d9cbaf81cfb@tantorlabs.com
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On 14.04.2025 23:53, David Rowley wrote:
> If we can't get consensus for everything people want to add at once
> then maybe the patch could be broken into two, with 0001 being pretty
> much the v4 patch and then have 0002 add the Estimated Hit Ratio.
> Having the physical patches and being able to try it out or view the
> regression test changes might lower the bar on people chipping in with
> their views.

Agreed - I’ll split the patch into two: one adds Estimated Capacity
and Estimated Distinct Keys, and the second adds Estimated Hit Ratio.
I’ll also add regression test differences to make it easier to evaluate
the usefulness of each part.

--
Best regards,
Ilia Evdokimov,
Tantor Labs LLC.

Attachment Content-Type Size
v7-0001-Show-ndistinct-and-est_entries-in-EXPLAIN-for-Mem.patch text/x-patch 32.8 KB
v7-0002-Add-Estimated-Hit-Ratio-for-Memoize-plan-nodes-in.patch text/x-patch 26.1 KB

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