Re: Why our Valgrind reports suck

Hi,

On 2025-05-09 11:29:43 -0400, Andres Freund wrote:
> We currently don't reset TopMemoryContext at exit, which, obviously, does
> massively increase the number of leaks. But OTOH, without that there's not a
> whole lot of value in the leak check...

Briefly looking through the leaks indeed quickly found a real seeming leak,
albeit of limited size:
ProcessStartupPacket() does
    buf = palloc(len + 1);
in TopMemoryContext() without ever freeing it.


I have wondered if we ought to have some infrastructure to tear down all
relcache, catcache entries (and other similar things) before shutdown if
MEMORY_CONTEXT_CHECKING is enabled. That would make it a lot easier to see
leaks at shutdown. We certainly have had leaks in relcache etc...

Greetings,

Andres Freund