Estimating Statistics for Generating Execution Plans for Database Queries

A non-transitory computer readable storage medium storing instructions thereon, the instructions for:

• receiving a plurality of database queries by a database system, the database queries processing data stored in database tables of the database system;
• identifying 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;
• and
• performing statistical analysis to determine at least a subset of the identified missing statistics for use in generating execution plans for subsequent database queries.

A computer-implemented system for generating statistics for a database system, the system comprising:

• a computer processor;
• and
• a computer-readable storage medium storing instructions thereon, the instructions for:
• receiving a plurality of database queries by a database system, the database queries processing data stored in database tables of the database system;
• identifying 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;
• and
• performing statistical analysis to determine at least a subset of the identified missing statistics for use in generating execution plans for subsequent database queries.