Re: A design for amcheck heapam verification

On Fri, Sep 29, 2017 at 4:17 PM, Michael Paquier
<michael(dot)paquier(at)gmail(dot)com> wrote:
>> As for DSM, I think that that can come later, and can be written by
>> somebody closer to that problem. There can be more than one
>> initialization function.
>
> I don't completely disagree with that, there could be multiple
> initialization functions. Still, an advantage about designing things
> right from the beginning with a set of correct APIs is that we don't
> need extra things later and this will never bother module maintainers.
> I would think that this utility interface should be minimal and
> portable to maintain a long-term stance.

FWIW I think if I were attacking that problem the first thing I'd
probably try would be getting rid of that internal pointer
filter->bitset in favour of a FLEXIBLE_ARRAY_MEMBER and then making
the interface look something like this:

extern size_t bloom_estimate(int64 total elems, int work_mem);
extern void bloom_init(bloom_filter *filter, int64 total_elems, int work_mem);

Something that allocates new memory as the patch's bloom_init()
function does I'd tend to call 'make' or 'create' or 'new' or
something, rather than 'init'. 'init' has connotations of being the
second phase in an allocate-and-init pattern for me. Then
bloom_filt_make() would be trivially implemented on top of
bloom_estimate() and bloom_init(), and bloom_init() could be used
directly in DSM, DSA, traditional shmem without having to add any
special DSM support.

--
Thomas Munro
http://www.enterprisedb.com