(2019/01/11 13:49), Amit Langote wrote:
On 2019/01/11 11:21, Etsuro Fujita wrote:
(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.
Agreed.
Cool!
Improving planning performance for large number of partitions
even in the absence of pruning is a good goal to pursue for future
versions, as is being discussed in some other threads [1].
Yeah, we have a lot of challenges there. Thanks for sharing the info!
Best regards,
Etsuro Fujita
