Known issue - Concurrent stored procedures block each other in data warehouse
You can execute the same stored procedure in parallel in a data warehouse. When the stored procedure is run concurrently, it causes blocking because each stored procedure takes an exclusive lock during plan generation.
Status: Open
Product Experience: Data Warehouse
Symptoms
You might experience slowness when the same procedure is executed in parallel as opposed to by itself.
Solutions and workarounds
To relieve the slowdown, you can execute the stored procedures serially. Alternatively, you can let the procedures block each other and execute your new query once the block is released.