Ncr Corporation

Teradata Us, Inc.

Jeetendra Chaware

Douglas Paul Brown

Paul Laurence Sinclair

Manjula Koppuravuri

Thomas Patrick Julien

Mark Sirek

Rolf Günter Erich Stegelmann

Sunanda K Reddy

An index selection mechanism allows for efficient generation of index recommendations for a given workload of a database system. The workload includes a set of queries that are used to access tables in a database system. The index recommendations are validated to verify improved performance, followed by application of the indexes. Graphical user interface screens are provided to receive user input as well as to present reports to the user.

Index selection in a database system

A database system includes components for executing stored procedures that include at least one of a conditional expression, assignment expression, and dynamic database query language (e.g., SQL) statement. For each such expression, a predetermined type of code is generated and inserted into the object code corresponding to the stored procedure. When executing the stored procedure object code, the predetermined type of code is evaluated directly without having to generate a separate database query language statement.

Evaluating expressions in stored procedures

A system emulation tool and method provides a user interface having various options that are selectable by a user for exporting environment information from one or more target database systems. The user interface in one arrangement includes multiple screens that are invoked in response to user action. Exported data from the one or more target database systems is stored in corresponding files. The user interface of the system emulation tool also provides options to enable a user to import the environment information to a test system. In the test system, the environment information is used to create an environment that emulates the environment of the target database system.

Capturing database system information

An execution plan of a query for a parallel database system is determined. In one arrangement, the parallel database system is a relational database management system. The execution plan of the query is determined by an optimizer program. Execution plans are inserted into one or more explain tables that are accessible by a visual explain and compare module to display the steps of the execution plan in a graphical user interface. Parallel execution of steps of the execution plan can be depicted in the graphical user interface. Further, plural execution plans for a given query under different conditions may be compared.

Presenting query plans of a database system

A method and apparatus provides for the extraction of environment information from a target database system. The environment information includes at least one of cost-related information and random sample statistics. The cost-related information and/or random sample statistics are imported to a test system, where the cost-related information and/or random sample statistics are used in query plan analysis by an optimizer.

Emulating a database system

A method and computer system for structure subset generation for multiple databases is disclosed. The method retrieves a database view object structure. The method includes inputting definition language specifying a database view identifier and with at least one directly or indirectly referenced database object unqualified with a containing database identifier. The method further includes inputting a show statement that identifies the database view identifier and outputting the definition language with each directly or indirectly referenced database object qualified with its containing database identifier.

System and method for structure subset generation for multiple databases

Statistics regarding at least one attribute (or column) of a table in a database system are collected using an enhanced mechanism for faster collection. The statistics collection is based on scanning a sample of rows of a given table, with the sample being less than all the rows of the table. The percentage of rows to be read is specified in a statement submitted to the database system. The database system then uses the specified percentage to read the sample rows from the table for collecting statistics on the at least one attribute.

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Andhra Pradesh, India

Jeetendra Chaware