Re: Postgres: Queries are too slow after upgrading to PG17 from PG15

Tom Lane <tgl@sss.pgh.pa.us>

From: Tom Lane <tgl@sss.pgh.pa.us>

To: Sajith Prabhakar Shetty <ssajith@blackduck.com>

Cc: "pgsql-bugs@lists.postgresql.org" <pgsql-bugs@lists.postgresql.org>

Date: 2025-05-15T15:46:31Z

Lists: pgsql-bugs

Commits

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

Convert strategies to and from compare types
- c09e5a6a0165 18.0 cited
Enhance nbtree ScalarArrayOp execution.
- 5bf748b86bc6 17.0 cited
Improve planning of btree index scans using ScalarArrayOpExpr quals.
- a4523c5aa534 9.5.0 cited
Fix planning of btree index scans using ScalarArrayOpExpr quals.
- 807a40c551dd 9.3.0 cited

Sajith Prabhakar Shetty <ssajith@blackduck.com> writes:
> Now surprisingly one of the query i took from application which used to execute in 2s in PG15, is now taking 1min+ in PG17.

The data you've actually showed us does not back up that complaint.
But I do see a 2x slowdown.

> Explain plan of the two queries almost same, all the joins and paths used are exactly same.

Yeah, that is odd.  The only simple explanation I can think of is that you
are using a debug build of v17.

			regards, tom lane