Also, architectural changes. They describe how ES can't parallelize a query unless it's spread across multiple index shards, which has its own tradeoffs. Their

Also, architectural changes. They describe how ES can't parallelize a query unless it's spread across multiple index shards, which has its own tradeoffs. Their query engine can parallelize a query on a single index shard, which means it scales much more linearly on more cores without having to make those tradeoffs.