Re: _mdfd_getseg can be expensive - Mailing list pgsql-hackers

From Tom Lane
Subject Re: _mdfd_getseg can be expensive
Date
Msg-id 5725.1414861060@sss.pgh.pa.us
Whole thread Raw
In response to Re: _mdfd_getseg can be expensive  (Andres Freund <andres@2ndquadrant.com>)
Responses Re: _mdfd_getseg can be expensive  (Andres Freund <andres@2ndquadrant.com>)
List pgsql-hackers
Andres Freund <andres@2ndquadrant.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



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