Scott Frazer wrote: > Currently this seems to be happening when the server just starts taking > connections. It doesn't even need time to scale up anymore (previously it > took about 8 hours for the problem to re-appear) > > It's only happening on the read replicas, though. I've just set my master > to handle all the traffic, but that's not really sustainable I failed to notice at start of thread that these were replicas. I suppose then you would have to be thinking about the range of XIDs in the primary server. Maybe you left some old transaction open, or an uncommitted prepared transaction there? If not, I suppose you're up for some "perf" profiling ... -- Álvaro Herrera https://www.2ndQuadrant.com/ PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services