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

Ilia Evdokimov <ilya.evdokimov@tantorlabs.com>

From: Ilia Evdokimov <ilya.evdokimov@tantorlabs.com>

To: David Rowley <dgrowleyml@gmail.com>

Cc: Robert Haas <robertmhaas@gmail.com>, Tom Lane <tgl@sss.pgh.pa.us>, Lukas Fittl <lukas@fittl.com>, Daniel Gustafsson <daniel@yesql.se>, PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>, Nikolay Samokhvalov <samokhvalov@gmail.com>, Andrei Lepikhov <lepihov@gmail.com>

Date: 2025-07-04T08:30:53Z

Lists: pgsql-hackers

Attachments

v10-0001-Expose-cache-hit-statistics-in-Memoize-node-EXPLAIN.patch (text/x-patch)

On 01.05.2025 15:22, Ilia Evdokimov wrote:

> I attached updated v9 patch with the suggested changes. The updated 
> line in the EXPLAIN looks like this:
>
> Text format:
>     Estimates: capacity=1 distinct keys=1 lookups=2 hit percent=50.00%
>
> Non-text format:
>     Estimated Capacity: 1
>     Estimated Distinct Lookup Keys: 1
>     Estimated Lookups: 2
>     Estimated Hit Percent: 50.00
>
> Any suggestions?


I attached rebased v10 patch on 5a6c39b.

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