International Business Machines Corporation

Robert Russell Nelson

John Matthew Santosuosso

Brian Robert Muras

Brian John Cragun

Harvey Gene Kiel

Cale T Rath

Jordi A Albornoz

Kyle Lane Henderson

Lee David Feigenbaum

Stephen A Knight

Pamela A Wright

Mark Arnold Boegel

Douglas O Bolstad

An apparatus and method to optimize a query access plan in a computer database system. In preferred embodiments, the query optimizer determines the query can be optimized and generates for the query an optimized access plan that eliminates records defined by a Where clause and one or more ordering criteria prior to ordering the records (sorting or grouping) and then returning a first n rows.

Optimizing a computer database query that fetches N rows

Optimizing a database query that fetches N rows

Methods, systems, and articles of manufacture for maintaining annotations for changing source documents are provided. For some embodiments, an annotation system may support multiple policies, with each policy dictating how (or if) an annotation created for a version of a source document should be applied to subsequent versions of the source document. For some embodiments, a user creating an annotation may select from a group of available policies to be applied to the annotation.

Dealing with annotation versioning through multiple versioning policies and management thereof

Optimizing a computer database query that fetches n rows

Optimizing a database query that returns a predetermined number of rows using a generated optimized access plan

A computer system comprises a CPU, a main memory, and plurality of I/O Processors (IOPs), coupled to each other by a system I/O bus. The IOPs perform slave processing functions relating to I/O devices. A simulation protocol is defined for the IOPs, whereby the host CPU can command an IOP to execute a simulation script. The simulation script defines one or more I/O devices to be simulated, and specifies a simulated workload associated with the devices. The IOP executes the simulation script by sending simulated input streams to the host and receiving output destined for the simulated I/O devices from the host on the system I/O bus. An IOP may simulate multiple I/O devices, and may simulate I/O devices concurrently with servicing real I/O devices. In typical use, one or more applications programs will execute on the CPU concurrently with the execution of one or more simulation scripts in the IOPs attacked to the system I/O bus. The behavior of the system under such conditions can be used for capacity planning forecasts, for developing and debugging the application software, for reproducing and diagnosing intermittent error conditions, or for performing other tasks in which it is necessary to determine the characteristics of the system under hypothetical conditions.

Method and apparatus for simulating I/O devices

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Rochester, MN, United States of America

Robert Russell Nelson