DESCRIPTION:
Fix Bug #4949 where Blocking shard moves fails if there is a foreign key between partitioned distributed tables (from child to parent). This is because we try to create constraints before attaching child partitions to parent. This causes constraint failure as parent table will be empty. Fix is to reverse the order i.e. attach partitions before we create constraints.
TESTING:
Added a new test 'shard_move_constraints_blocking' inspired for existing 'shard_move_constraints' where we trigger shard move with 'block_writes' instead of 'force_logical' to add coverage for this scenario.
Nitish Upreti