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It seems the parallel aggregation increases efficiency of queries linearly with regard to CPUs, close to "perfect parallelisation." I have some 8-core boxes run
by aorth 11y ago
It seems the parallel aggregation increases efficiency of queries linearly with regard to CPUs, close to "perfect parallelisation." I have some 8-core boxes running PostgreSQL and this is still good to know.
- kitd 11y agoIt looks good up to 30 parallel worker processes. It does start to diverge a bit after that, but still very impressive.
- pgaddict 11y agoI'm not sure "efficiency" is the right term here. My understanding is that to get "more efficient" execution, you'd have to perform better with the same amount of resources. But parallelism allows using more resources (particularly CPU cores) for a query, while the overall efficiency (the total number of instructions, CPU time etc.) remains about the same. It's just that it's split over multiple cores. So if all CPU cores are already saturated on your machine (e.g. because you're already running multiple queries), it's not going to improve things.