@henryccook made an interesting point regarding Netezza workload management this morning… He suggested that once a SPU is engaged by a snippet the work must be completed before another snippet can start. To say this another way… a SPU has no OS and cannot save context for a snippet and start another… then return.
If this is true it means that if a long-running snippet starts… a full file scan of a fact table with no use of the zone map… then that snippet will lock out others queries until it completes.
This is not a very fine-grained approach to workload management and we would expect it to cause difficulties.
Can anyone confirm that this is true? It feels right from an architectural perspective…