Understanding workload management
A Synapse Analytics SQL pool is a scale-out SQL implementation. Even though it is a scale-out system, resources might be scarce and they are expensive. You need to be able to regulate how your resources are utilized by your queries. Assigning resources to queries is called workload management.
There is a trade-off to consider. A Synapse SQL pool can today execute 128 concurrent queries. If you do have 128 concurrent queries, all available resources are divided over those queries, which means that each query only has a limited number of resources it can use. Resources are a combination of I/O, memory, and CPU. When bulk-loading a columnstore table, you need your query to be able to utilize a lot of memory. With too many concurrent queries, your bulk-load query might not have enough memory. You can assign more resources to a query but that means you can run fewer queries concurrently.
To understand the memory requirement of bulk-load queries, we...