Hi Tom,
a few tests later.
Looks like when you add a partition as default, all tupples of it are read, even if there is an index on the column that is the partition key.
this do explain our attach time. We are going to clean the default partition...
regards,
On Tue, Jul 14, 2020 at 7:05 PM Tom Lane <tgl@xxxxxxxxxxxxx> wrote:
Marc Millas <marc.millas@xxxxxxxxxx> writes:
> We would like to understand where an alter table attach partition spend its
> time.
> to my understanding, explain doesnt do this.
Nope :-(. As our DDL commands have gotten more complicated, there's
been some discussion of adding that, but nothing's really been done
yet.
There is some progress-monitoring support for some DDL commands now,
but that's not quite the same thing.
> for a BI job we have a partitionned table with 1800+ partitions.
TBH I'd recommend scaling that down by at least a factor of ten.
We are not at a point where you can expect that all operations will
be cheap even with thousands of partitions. We may never be at that
point, although people continue to chip away at the bottlenecks.
regards, tom lane
