Parameter · Developer Options
jit_dump_bitcode
Write out LLVM bitcode to facilitate JIT debugging.
- Default:
off - Type: bool
- Applies: Session (superuser)
In plain words
Saves the intermediate code (LLVM bitcode) that the JIT compiler generated to files in the data directory. Only useful to people working on the JIT code itself.
For DBAs and operators
Files are named like <pid>.<n>.bc (plus <pid>.<n>.optimized.bc after the optimisation pass) in data_directory, and can be read with llvm-dis. Every JIT-compiled query adds files, and nothing deletes them, so a busy server quickly accumulates clutter in $PGDATA. Turn it on in one session (it is superuser-settable), run the query, turn it off.
Developer option: meant for debugging and testing PostgreSQL itself. Leave it at the default on production servers unless a specific diagnosis calls for it.
How to change it
A superuser (or a role granted SET) can change it per session with SET.