System and method for performing database operations on a continuous stream of tuples

A method of processing a stream of data in a database management system, in accordance with a specified query, comprising:

• using a scan operator, performing an initial scan to access a defined range of rows in the database table;
• while performing the initial scan, building a list of rows that become available during the initial scan and that fall within the defined range of rows in the database table;
• using the scan operator, performing a secondary scan to access rows included in the list;
• while performing the secondary scan, adding to the list rows that become available after the initial scan and that fall within the defined range of rows in the database table;
• and
• processing the accessed rows in accordance with the specified query.

A database management system, comprising:

• a database, including a plurality of tables, each table storing data in one or more rows;
• an execution engine for executing a streaming mode query, for processing a stream of data, the execution engine including a scan operator for accessing a defined range of rows in a specified one of the database tables;
• the scan operator including:
• initial scan instructions for performing an initial scan to access the defined range of rows in the specified table;
• a list data structure for storing a list of references to rows, if any, in the specified table that become available during the initial scan and that fall within the defined range of rows in the specified table;
• and
• secondary scan instructions for performing a secondary scan to access rows referenced in the list data structure.

A computer program product for use in conjunction with a computer system, the computer system including a database, including a plurality of tables, each table storing data in one or more rows;

• the computer program product comprising a computer readable storage medium and a computer program mechanism embedded therein, the computer program mechanism comprising:
• an execution engine for executing a streaming mode query, for processing a stream of data, the execution engine including a scan operator for accessing a defined range of rows in a specified one of the database tables;
• the scan operator including:
• initial scan instructions for performing an initial scan to access the defined range of rows in the specified table;
• a list data structure for storing a list of references to rows, if any, in the specified table that become available during the initial scan and that fall within the defined range of rows in the specified table;
• and
• secondary scan instructions for performing a secondary scan to access rows referenced in the list data structure.

A method of processing a stream of data in a database management system, in accordance with a specified query, comprising:

• using a scan operator, scanning a defined range of rows in a database table in accordance with the specified query, and returning qualifying rows in the defined range to a calling application;
• using the scan operator, suspending operation of the scanning step when there are no qualifying rows in the defined range;
• and
• automatically resuming operation of the scanning step after one or more qualifying rows in the defined range in the database table become available.

A database management system, comprising:

• a database, including a plurality of tables, each table storing data in one or more rows;
• an execution engine for executing a streaming mode query, for processing a stream of data, the execution engine including a scan operator for accessing a defined range of rows in a specified one of the database tables;
• the scan operator including:
• instructions for scanning a defined range of rows in a database table in accordance with the specified query, and returning qualifying rows in the defined range to a calling application;
• and
• instructions for suspending operation of the scan operator when there are no qualifying rows in the defined range;
• and
• the execution engine including instructions for automatically resuming operation of the scan operator after one or more qualifying rows in the defined range become available in the database table.

A computer program product for use in conjunction with a computer system, the computer system including a database, including a plurality of tables, each table storing data in one or more rows;

• the computer program product comprising a computer readable storage medium and a computer program mechanism embedded therein, the computer program mechanism comprising:
• an execution engine for executing a streaming mode query, for processing a stream of data, the execution engine including a scan operator for accessing a defined range of rows in a specified one of the database tables;
• the scan operator including:
• instructions for scanning a defined range of rows in a database table in accordance with the specified query, and returning qualifying rows in the defined range to a calling application;
• and
• instructions for suspending operation of the scan operator when there are no qualifying rows in the defined range;
• and
• the execution engine including instructions for automatically resuming operation of the scan operator after one or more qualifying rows in the defined range become available in the database table.