On Tue, Apr 17, 2012 at 12:12 AM, Jeff Davis
<pgsql@j-davis.com> wrote:
Thank you, that's exactly the kind of overview I was looking for.
> It shows that there is a lot of methods based on building temporaty
> indexes. It might mean that building of temporary GiST index is not a
> bad idea.
That had occurred to me, but I was hesitant to only use temp indexes. It
still doesn't really offer a good solution when both sides of the join
are relatively large (because of random I/O). Also the build speed of
the index would be more important than it is now.
Note, that amount of random I/O during GiST index build significanlty dicreased after my GSoC project for buffering GiST index build. However, GiST index build is still quite CPU-expensive. This problem could be evaded by support of another methods of index build (another than producing a lot of penalty and picksplit calls). Hilbert curve and similar methods could help here. Implementation of such methods would require extension of GiST interface.
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With best regards,
Alexander Korotkov.