Investigating and reporting a bug
It is a good idea to make a full copy of your PostgreSQL installation before you start investigating. This will help you restart several times and be sure that you are investigating the results of the bug, and not chasing your tail by looking at changes that were introduced by your last investigation and debugging attempt.
Do not forget to include your tablespaces in the full copy.
How to do it…
Try to make a minimal repeatable test scenario that exhibits this bug. Sometimes, the bug disappears while doing this, but mostly, it is needed to make the process easy. It is almost impossible to fix a bug that you can't observe and repeat at will.
If it is about query processing, then you can usually provide a minimal dump file (the result of running
pg_dump) of the specific tables, together...