Re: Patch: Optimize memory allocation in function 'bringetbitmap'

zhangjinyu wrote:

> >>>>However I wonder if it would be simpler to have the dtup structure have
> >>>>the pointers, so that you can pass it as NULL in the first call and then
> >>>>followup calls reuse the one allocated in the first call.
> Jinyu: the memory is allocated from perRangeCxt and perRangeCxt will be
> reset in loop,
> so this way don't work.

You're right. I think we can do better: have brin_deform_tuple accept
another argument of type BrinMemTuple *, which can be NULL. If NULL,
the function calls brin_new_memtuple to allocate a new one (just like
current code); if not NULL, that one is used. Have brin_new_memtuple
also allocate the values/allnulls/hasnulls arrays, which are now part of
the BrinMemTuple struct. Then, bringetbitmap calls brin_new_memtuple
once before changing to perRangeCxt, then reuse the returned inside the
loop (we probably need brin_memtuple_initialize to clear out the struct
at the end of each loop iteration). Other callers of brin_deform_tuple
just pass NULL to get the current behavior.

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Álvaro Herrera http://www.2ndQuadrant.com/
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