On Sun, May 15, 2016 at 10:22 AM, Anderson Carniel <accarniel@gmail.com> wrote:
> Thank you very much Joe.
>
> I have followed the crosstab() implementation and understood the idea of per
> query memory context. Now, I am using a unique SPI instance (which I perform
> several sql queries), process the result, transform my result into a
> tuplestore, close the SPI and done. It works perfectly.
>
> I have a curiosity with regard to the tuplestore: is there a problem with
> performance if my tuplestore form a big table with million of tuples? Other
> question is regarding to SPI: is there a problem to use only one instance
> of SPI (for instance, if multiple users call the same function)?
When using a tuplestore, one concern for performance is the moment
data is going to spill into disk, something that is set with maxKBytes
in tuplestore_begin_heap(). Using work_mem is the recommendation,
though you could tune it better depending on your needs.
--
Michael