Re: Confusing comment in tidbitmap.c

David Rowley <dgrowleyml(at)gmail(dot)com> writes:
> The following comment above #define PAGES_PER_CHUNK in tibbitmap.c appears
> to be incorrect:

> "But we
> * also want PAGES_PER_CHUNK to be a power of 2 to avoid expensive integer
> * remainder operations. So, define it like this:"

> I don't quite follow this as it does nothing of the kind.
> Check tbm_page_is_lossy() where we do: bitno = pageno % PAGES_PER_CHUNK;

> Or am I missing something about the compiler optimizing that to: bitno =
> pageno & 255; ?

Exactly. Any C compiler ever written will do that.

regards, tom lane