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.
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. 13. The non-transitory computer readable storage medium of claim 12 , wherein the requested statistical information is associated with one or more columns of database tables and wherein storing information describing the requested statistical information comprises storing information identifying the one or more columns.