Re: [EXTERNAL] Re: BUG #19114: ORDER BY ASC is tampering result when calculating distance btw vectors

Hi Thomas,

Very good day!
As you referred I am able to confirm the following:

1.
The issue is occurring when HNSW indexing is done.
2.
The issue is not replicable with vector extension 0.8.0
3.
I have tried with multiple m and ef_construction pairs ranging from (16,200) to (64,512) and nothing is working.

May I know where could I see the release updates on 0.8.1 of the vector extension?
Also please feel free to share your thoughts for me to test more on the same.

Thanks and regards,
Naveen Krishna

From: Thomas Munro <thomas(dot)munro(at)gmail(dot)com>
Date: Monday, 17 November 2025 at 1:21 PM
To: S, Naveen Krishna (Development Engineer 3) <naveenkrishna(dot)s(at)sky(dot)uk>, pgsql-bugs(at)lists(dot)postgresql(dot)org <pgsql-bugs(at)lists(dot)postgresql(dot)org>
Subject: [EXTERNAL] Re: BUG #19114: ORDER BY ASC is tampering result when calculating distance btw vectors

On Mon, Nov 17, 2025 at 7:14 PM PG Bug reporting form
<noreply(at)postgresql(dot)org> wrote:
> 40 records

Sounds like pgvector[1]?

"Why are there less results for a query after adding an HNSW index?
Results are limited by the size of the dynamic candidate list
(hnsw.ef_search), which is 40 by default. ...."

[1] https://urldefense.com/v3/__https://github.com/pgvector/pgvector__;!!IlCVUJ0!pgEkbcfGC71pECmG2FAxk-UVuOknYxbjtoQO3yaM1g09YxwPgPSDF9XXWQgCAxG3rmlFOkoesem_tILjQC_EsxIduQ$
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