Hello! Thanks for checking the issue!
> FWIW, I find that the "Assert(ItemIdIsNormal(lp));" at the top of > heap_lock_tuple() is the first thing that fails on my assert-enabled > build. Yes, the same for me: TRAP: failed Assert("ItemIdIsNormal(lp)"), File: "heapam.c", Line: 4292, PID: 33416 > Reproduced this on HEAD locally (no docker), without any difficulty. It is a little bit harder without docker in my case, need to adjust connections and number of threads: pgbench -c 90 -j 8 -n -f reproduce.bench 'port= 5432 host=localhost user=postgres dbname=postgres password=postgres' -T 2000 -P 1 Best regards, Michail.