Re: Is element access after HASH_REMOVE ever OK?

Thomas Munro <thomas(dot)munro(at)gmail(dot)com> writes:
> However, I noticed in passing that RemoveLocalLock() accesses
> *locallock after removing it from the hash table (in assertion builds
> only). So one question I have is whether it's actually a programming
> rule that you can't do that (at most you can compare the pointer
> against NULL), or whether it's supposed to be
> safe-if-you-know-what-you're-doing, as the existing comments hints.

I'd say it's, at best, unwarranted familiarity with the dynahash
implementation ...

> Here also is a patch that does wipe_mem on removed elements, as
> threatened last time this topic came up[1], which reveals the problem.

... one good reason being that it'll fail under this sort of
entirely-reasonable debugging aid. Can we get rid of the unsafe
access easily?

regards, tom lane