12. A non-transitory computer readable storage medium storing instructions thereon, the instructions for execution by a computer processor to cause the computer processor to perform: receiving, by a query compiler from a client device, a plurality of database queries by a database system, the database queries processing data stored in database tables of the database system; identifying, by the query compiler, missing statistics while generating execution plans for database queries, the identifying comprising, for each of the plurality of database queries: requesting a statistical information useful for generating an execution plan for a database query; determining that the requested statistical information is not available; and storing information describing the requested statistical information as missing statistics, responsive to determining that the requested statistical information is not available; ranking the identified missing statistics based on a number of times each missing statistics was identified as being not available during generation of execution plan; determining a subset of the identified missing statistics for use in generating execution plans for subsequent database queries, wherein determining the subset comprises selecting identified missing statistics based on the ranking; receiving, by the query compiler, the subsequent database queries; generating, by the query compiler, an execution plan for the one of the subsequent database queries using at least one of the identified missing statistics from the subset; executing, by an execution engine, the generated execution plan for the one of the subsequent queries to determine a result set; and sending the determined result set to the client device.
14. The non-transitory computer readable storage medium of claim 12 , wherein identifying the missing statistics for a database query comprises: determining that the database query processes a plurality of columns; and responsive to determining that the database query processes a plurality of columns, identifying the statistical information to be a multi-column NDV of the plurality of columns.