(2019/01/10 21:23), Amit Langote wrote:
On Thu, Jan 10, 2019 at 6:49 PM Ashutosh Bapat
<ashutosh.bapat....@gmail.com> wrote:
Though this will solve a problem for performance when partition-wise join is
not possible, we still have the same problem when partition-wise join is
possible. And that problem really happens because our inheritance mechanism
requires expression translation from parent to child everywhere. That consumes
memory, eats CPU cycles and generally downgrades performance of partition
related query planning. I think a better way would be to avoid these
translations and use Parent var to represent a Var of the child being dealt
with. That will be a massive churn on inheritance based planner code, but it
will improve planning time for queries involving thousands of partitions.
Yeah, it would be nice going forward to overhaul inheritance planning
such that parent-to-child Var translation is not needed, especially
where no pruning can occur or many partitions remain even after
pruning.
I agree on that point, but I think that's an improvement for a future
release rather than a fix for the issue reported on this thread.
Best regards,
Etsuro Fujita
