Re: _mdfd_getseg can be expensive

Andres Freund <andres(at)2ndquadrant(dot)com> writes:
> On 2014-10-31 18:48:45 -0400, Tom Lane wrote:
>> While the basic idea is sound, this particular implementation seems
>> pretty bizarre. What's with the "md_seg_no" stuff, and why is that
>> array typed size_t?

> It stores the length of the array of _MdfdVec entries.

Oh. "seg_no" seems like not a very good choice of name then.
Perhaps "md_seg_count" or something like that would be more intelligible.

And personally I'd have made it an int, because we are certainly not doing
segment-number arithmetic in anything wider than int anywhere else.
Introducing size_t into the mix won't do anything except create a risk of
signed-vs-unsigned logic bugs.

regards, tom lane