Read replicas and stale reads

Back to list2026-05-09
You

Users see their own edits disappear after saving. Replica lag?

ChatGPT

Almost certainly. Route reads that follow a write by the same user to the primary for a short window, or track the write LSN in the session and wait for the replica to reach it. The general fix is read-your-writes consistency, not lower lag.

You

I deleted 12M rows and the index is still the same size. Why?

ChatGPT

Deleting rows marks them dead but leaves index entries until vacuum reclaims the pages, and even then the pages stay allocated to that index. REINDEX INDEX CONCURRENTLY is what actually returns the space.