On 2017-11-27 22:53:41 -0500, Tom Lane wrote:
> Tomas Vondra <tomas.vondra@2ndquadrant.com> writes:
> > I'm a bit puzzled by this code in SH_COMPUTE_PARAMETERS:
>
> > if (tb->size == SH_MAX_SIZE)
> > tb->sizemask = 0;
> > else
> > tb->sizemask = tb->size - 1;
>
> > Doesn't that mean that with SH_MAX_SIZE we end up with sizemask being 0
> > (i.e. no bits set)?
>
> Yeah, which is very obviously broken: for one thing, the Asserts
> in SH_NEXT/SH_PREV would surely go off.
That's obviously wrong. Not sure how that happened. I might have had it
as a shift at first?
> (Why are those assertions, anyway, and not test-and-elog?
> I do not think an assertion failure is a suitable way to
> report "hash table full".)
There's a test and elog during insert. Adding actual branches into
SH_NEXT/SH_PREV seems like a bad idea.
Will test a fix.
Greetings,
Andres Freund