Amazon Redshift now delivers better cold query performance by significantly improving compilation times
Amazon Redshift now processes queries 2x faster when they need to be compiled. This improvement gives you better query performance when you create a new Redshift cluster, onboard a new workload on an existing cluster, or after a software update of an existing cluster. These query performance improvements are available at no extra charge to you, and no action is needed to enable it on your clusters.
Source:: Amazon AWS