Re: On-demand running query plans using auto_explain and signals

But do we really need the slots mechanism?  Would it not be OK to just let the LWLock do the sequencing of concurrent requests?  Given that we only going to use one message queue per cluster, there's not much concurrency you can gain by introducing slots I believe.

I afraid of problems on production. When you have a queue related to any process, then all problems should be off after end of processes. One message queue per cluster needs restart cluster when some pathological problems are - and you cannot restart cluster in production week, sometimes weeks. The slots are more robust.