Robert Haas <robertmh...@gmail.com> writes: > On Mon, Jun 22, 2015 at 2:55 PM, Tom Lane <t...@sss.pgh.pa.us> wrote: >> If I recall that code correctly, the assumption was that if the third >> argument is zero then memcmp() must not fetch any bytes (not should not, >> but MUST not) and therefore it doesn't matter if we pass a NULL. Are >> you seeing any observable problem here, and if so what is it?
> I dunno, this seems like playing with fire to me. A null-test would > be pretty cheap insurance. A null test would be a pretty cheap way of masking a bug in that logic, if we ever introduced one; to wit, that it would cause a call with argtypes==NULL to match anything. Possibly saner is if (nargs == 0 || memcmp(argtypes, best_candidate->args, nargs * sizeof(Oid)) == 0) break; I remain unconvinced that this is necessary, though. It looks a *whole* lot like the guards we have against old Solaris' bsearch-of-zero-entries bug. I maintain that what glibc has done is exactly to introduce a bug for the zero-entries case, and that Piotr ought to complain to them about it. At the very least, if you commit this please annotate it as working around a memcmp bug. regards, tom lane -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers