Rails migration fails after upgrading from 24.1 to 24.2 - no indexes found & no support for composite primary keys

[mowinslow2]

After upgrading from 24.1 to 24.2, there is a no indexes found error and a no support for composite primary keys when running rails migration. This seems to be happening exclusively on Regional by Row tables with PKs and indexes that include the hidden crdb_region column

It looks like the culprit could be that the crdb_region column is now included in pg_index.indkey

Issue 1

== migrating ============================
-- remove_index(:redacted_table_name, "redacted_table_name_id", {:algorithm=>:concurrently})
rails aborted!
StandardError: An error has occurred, all later migrations canceled: (StandardError)

No indexes found on redacted_table_name with the options provided.

Caused by:
ArgumentError: No indexes found on redacted_table_name with the options provided. (ArgumentError)
            raise ArgumentError, "No indexes found on #{table_name} with the options provided."
Tasks: TOP => db:migrate

Issue 2

WARNING: Active Record does not support composite primary key.
redacted_table_name has composite primary key. Composite primary key is ignored.

[rafiss]

I am curious if table definitions like this also cause the issue:

CREATE TABLE t(a INT NOT VISIBLE, b INT, PRIMARY KEY (a,b));

CREATE TABLE t(a INT PRIMARY KEY USING HASH WITH (bucket_count=4));

[BuonOmo]

I've started looking for a reproduction on #345. The two create tables you showed @rafiss are simply not showing any index, and this didn't change since 23.2. Maybe because of the d.indisprimary = 'f' in the #indexes method. This looks like a behaviour we might not want, but it has nothing to do with the migration from 24.1 to 24.2.

I do not yet have access to a regional table plan to see if I can reproduce the reported issue. But I will soon hopefully!

EDIT: the bucket_count table seems to give us a fair reproduction !

---

Before we can find a clear fix, to remove the index you could use remove_index(:redacted_table_name, [:id, :crdb_region]). This should work.