Re: BUG #18885: ERROR: corrupt MVNDistinct entry - 2

Andrei Lepikhov <lepihov@gmail.com>

From: Andrei Lepikhov <lepihov@gmail.com>

To: tharakan@gmail.com, pgsql-bugs@lists.postgresql.org, PG Bug reporting form <noreply@postgresql.org>, Alexander Korotkov <aekorotkov@gmail.com>

Date: 2025-04-10T12:28:01Z

Lists: pgsql-bugs

Attachments

0001-Be-more-conventional-estimating-hash-join-bucket-siz.patch (text/x-patch) patch 0001

On 4/9/25 15:46, PG Bug reporting form wrote:
> The following SQL triggers "ERROR: corrupt MVNDistinct entry", however this
> seems to be unrelated to a recent bugfix[1] for a similar issue (thus '2' in
> the $SUBJECT).
That's my fault.
We wanted to avoid using of the add_unique_group_var, but forgot it does 
some necessary stuff.
Here, I attempt to use this routine in the hash join bucket size 
estimation. I transformed it a little, made it more general. Not sure it 
is the best design, but it is debatable.

-- 
regards, Andrei Lepikhov

Commits

Same data as JSON: GET /api/v1/messages/:b64id/commits the thread's linked commits as JSON, with link sources. API reference →

Properly prepare varinfos in estimate_multivariate_bucketsize()
- 9f404d7922e8 18.0 landed
Improve comments for estimate_multivariate_ndistinct()
- f3281f9f9395 18.0 landed
Use extended stats for precise estimation of bucket size in hash join
- 6bb6a62f3cc4 18.0 cited
Ignore nullingrels when looking up statistics
- e28033fe1af8 18.0 cited