Review section results in 500 server error for a specific moderator

zogstrip · October 12, 2026, 8:52pm

i found a way to optimize the query without using the OFFSET 0 trick

github.com/discourse/discourse

PERF: Check review queue visibility per topic for moderators (#44497)

main ← perf/review-queue-moderator-visibility

merged 08:26AM - 13 Oct 26 UTC

ZogStriP

+95 -30

Previously, the review queue built every visible topic and every private message… a moderator can see as whole-table subqueries (`topic_id IN (...)` and `NOT IN (...)`). On large sites, Postgres scanned millions of posts or rescanned the PM list once per reviewable. `/review` then timed out with a 500 for non-admin moderators (https://meta.discourse.org/t/414526). This change correlates those checks to each reviewable's topic with `EXISTS` / `NOT EXISTS`, so Postgres does index lookups per reviewable, with the same visibility rules. On a 1M topic / 8M post dataset, the count + page queries for a moderator drop from ~10–32s to ~0.5s, and the pending count from ~4.5s to ~50ms.

Topic		Replies	Views
Category Moderators may receive incorrect number of pending reviews Bug category-moderators , review-queue	0	83	August 7, 2026
Feedback on the new Review Queue (2019) Announcements new-feature , review-queue	260	21110	March 11, 2023
Proposal: Consolidated Review Queue Feature	33	6377	March 28, 2019
A new review queue layout with all new features Announcements review-queue	43	3008	September 20, 2026
App/models/topic_tracking_state - `report` - long response times? Development slow-sql	6	1932	February 26, 2016

Review section results in 500 server error for a specific moderator

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