Re: BUG #17821: Assertion failed in heap_update() due to heap pruning

Hello,

07.10.2023 11:00, Alexander Lakhin wrote:
>
> I've encountered another case of that assertion failure (this time with pg_statistic):

That second case is not reproduced anymore, after ad98fb142, but the first
is still actual.

I also discovered another one, with pg_subscription:
echo "
CREATE ROLE su SUPERUSER;
CREATE SUBSCRIPTION sub CONNECTION 'dbname=nonexisting'
   PUBLICATION pub WITH (connect = false);
" | psql

for ((i=1;i<=20;i++)); do
   echo "iteration $i"

   for ((k=1;k<=100;k++)); do
     for ((j=1;j<=200;j++)); do echo "
ALTER SUBSCRIPTION sub SET (synchronous_commit = false);
     "; done | psql >/dev/null 2>&1 &

     for ((j=1;j<=200;j++)); do echo "
ALTER SUBSCRIPTION sub OWNER TO su;
ALTER SUBSCRIPTION sub SET (slot_name = NONE);
     "; done | psql >/dev/null 2>&1 &
     wait
   done

   grep 'TRAP:' server.log && break;
done

This script fails for me as below:
...
iteration 5
TRAP: failed Assert("ItemIdIsNormal(lp)"), File: "heapam.c", Line: 3296, PID: 388093

(sed 's/minfree = Max(minfree, BLCKSZ \/ 10)/minfree = Max(minfree, BLCKSZ \/1)/'
-i src/backend/access/heap/pruneheap.c
is highly recommended for reproducing)

Melanie and Heikki, as you have been working on pruning over the recent
months, perhaps this defect could be of interest to you...

Best regards,
Alexander