Rework SLRU I/O errors handle

Maxim Orlov <orlovmg@gmail.com>

From: Maxim Orlov <orlovmg@gmail.com>

To: Postgres hackers <pgsql-hackers@lists.postgresql.org>

Date: 2026-02-26T14:26:05Z

Lists: pgsql-hackers

Attachments

v3-0003-Use-custom-SLRU-IO-error-msg-for-an-asynchronous-.patch (application/octet-stream) patch v3-0003
v3-0005-Avoid-misleading-user-about-status-of-InvalidTran.patch (application/octet-stream) patch v3-0005
v3-0001-Add-a-callback-for-generating-an-I-O-message-in-t.patch (application/octet-stream) patch v3-0001
v3-0002-Add-test-case-for-custom-SLRU-IO-error.patch (application/octet-stream) patch v3-0002
v3-0004-Use-custom-SLRU-IO-error-msg-for-multixact.patch (application/octet-stream) patch v3-0004
v3-0006-Expand-xact-SLRU-IO-error-to-show-epoch.patch (application/octet-stream) patch v3-0006

Hi!

Beginning of the discussion is here [0].

Historically, the SLRU module was designed to handle 32-bit
transactions. However, it is now utilised for handling a variety of
object types, like TransactionId, MultixactId, MultiXactOffset,
QueuePosition, and so on. But the IO error reporting system is still
designed to support 32-bit XIDs exclusively.

The proposed patchset allows us to define a "custom" callback to
improve error messages.

The first two commits add a callback and test case. The subsequent ones
improve I/O error messages. The last one adds the XID epoch to the error
message. It's purely optional, but I think it would be useful.

[0]
https://www.postgresql.org/message-id/CACG%3Dezbwy1zargXDNPeYXxZwRW3jXu_aD%3DrcG-7dc4fw7Y9Ojw%40mail.gmail.com

-- 
Best regards,
Maxim Orlov.

Commits

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

Add callback for I/O error messages in SLRUs
- f9de9bf302d2 19 (unreleased) landed