Re: how to create index concurrently on partitioned table

On Thu, Jun 11, 2020 at 10:35:02AM -0500, Justin Pryzby wrote:
> Note, you could do this now using psql like:
> SELECT format('CREATE INDEX CONCURRENTLY ... ON %s(col)', a::regclass) FROM pg_partition_ancestors() AS a;
> \gexec

I have skimmed quickly through the patch set, and something has caught
my attention.

> drop table idxpart;
> --- Some unsupported features
> +-- CIC on partitioned table
> create table idxpart (a int, b int, c text) partition by range (a);
> create table idxpart1 partition of idxpart for values from (0) to (10);
> create index concurrently on idxpart (a);
> -ERROR: cannot create index on partitioned table "idxpart" concurrently
> +\d idxpart1

When it comes to test behaviors specific to partitioning, there are in
my experience three things to be careful about and stress in the tests:
- Use at least two layers of partitioning.
- Include into the partition tree a partition that has no leaf
partitions.
- Test the commands on the top-most parent, a member in the middle of
the partition tree, the partition with no leaves, and one leaf, making
sure that relfilenode changes where it should and that partition trees
remain intact (you can use pg_partition_tree() for that.)

That's to say that the amount of regression tests added here is not
sufficient in my opinion.
--
Michael