We are pleased to announce that Azure SQL Data Warehouse (Azure SQL DW) now supports automatic creation of column level statistics. Azure SQL DW is a fast, flexible, and secure analytics platform for the enterprise.
Modern systems such as Azure SQL DW, rely on cost-based optimizers to generate quality execution plans for user queries. Even though Azure SQL DW implements a cost-based optimizer, the system relies on developers and administrators to create statistics objects manually. When all queries are known in advance, determining what statistics objects need to be created is an achievable task. However, when the system is faced with ad-hoc and random queries which is typical for the data warehousing workloads, system administrators may struggle to predict what statistics need to be created leading to potentially suboptimal query execution plans and longer query response times. One way to mitigate this problem is to create statistics objects on all the table columns in advance. However, that process comes with a penalty as statistics objects need to be maintained during table loading process, causing longer loading times.