Re: [PATCH] we have added support for box type in SP-GiST index

>>> I'll try to explain with two-dimensional example over points. ASCII-art:
>>
>> Thank you for the explanation.  Should we incorporate this with the patch.
>
> added

I have worked on the comments of the patch.  It is attached.  I hope
it looks more clear than it was before.

>>> + cmp_double(const double a, const double b)
>>
>> Does this function necessary?  We can just compare the doubles.
>
> Yes, it compares with limited precision as it does by geometry operations.
> Renamed to point actual arguments.

I meant that we could use FP macros directly instead of this function.
Doing so is also more correct.  I haven't tried to produce the
problem, but this function is not same as using the macros directly.
For differences smaller that the epsilon, it can return different
results.  I have removed it on the attached version.

>>> + boxPointerToRangeBox(BOX *box, RangeBox * rectangle)
>>
>> The "rectangle" variable in here should be renamed.
>
> fixed

I found a bunch of those too and renamed for clarity.  I have also
reordered the arguments of the helper functions to keep them
consistent.

> evalRangeBox() is used to initialize fields of RangeBox in evalRectBox(). If
> evalRangeBox() will palloc its result then we need to copy its result into
> RangeBox struct and free. Let both fucntion use the same interface.

I found it nicer to copy and edit the existing value than creating it
in two steps like this.  It is also attached.

> it works until allthesame branch contains only one inner node. Otherwise
> traversalValue will be freeed several times, see spgWalk().

It just works, when traversalValues is not set.  It is also attached.

I have also added the missing regression tests.  While doing that I
noticed that some operators are missing and also added support for
them.  It is also attached with the updated version of my test script.

I hope I haven't changed the patch too much.  I have also pushed the
changes here:

https://github.com/hasegeli/postgres/commits/box-spgist