101 questions to ask when dating - Sql commands for updating table
" This question is not one that can be answered by the age of the data.
An up-to-date statistics object might be old if there's been no material change to the underlying data.
However, if your data warehouse only contains one country and you bring in data from a new country, resulting in data from multiple countries being stored, then you need to update statistics on the country column.
The options that you use for each column depend on the characteristics of your data and how the column will be used in queries.
To create statistics on a column, simply provide a name for the statistics object and the name of the column. By default, SQL Data Warehouse samples 20 percent of the table when it creates statistics.
Recommendations and examples for creating and updating query-optimization statistics on tables in Azure SQL Data Warehouse.
The more Azure SQL Data Warehouse knows about your data, the faster it can execute queries against it.
Automatic creation of statistics is currently turned on by default.