摘要:
The select statement of a query is processed to determine whether any of the columns in the select statement appear in the predicate of the query. For each column in the select statement that also appears in the predicate of the query, the column may be eliminated from the result set by writing the value for the column in a side data structure. In this manner, the amount of data returned in the result set is reduced, thereby enhancing system performance in running the query.
摘要:
A method, system and article of manufacture for query execution management in a data processing system and, more particularly, for managing execution of queries including user-defined functions. One embodiment provides a method for managing execution of a query against data of a database. The method includes receiving a query against the data of the database, the query having at least one query condition including a user-defined function. It is determined whether the user-defined function satisfies a predefined index applicability criterion. If the user-defined function satisfies the predefined index applicability criterion, an index over relevant data of the database is created for the user-defined function. The index is suitable for use in execution of the query against the data of the database to determine a corresponding query result.
摘要:
A database monitor tracks performance statistics and information about the execution of different SQL statements. In particular, the monitor tracks information about the individual instructions that comprise a complex query. The performance statistics and information from these individual elements provide insight into a query's performance and may show why a query's performance is below expectations.
摘要:
A portable phone is equipped with a position detector that detects the geographical position of the portable phone, and a telephone system may ring one or more land-based phones or portable phones according to the geographical position of the portable phone. One or more geographical regions are defined, with corresponding telephone parameters defined for each region. When a portable phone enters a defined region, exits a defined region, or changes between two defined regions, the function of one or more land-based phones or portable phones may change. The preferred embodiments thus allow changing the function of one or more other phones based on the self-detected geographical position of a portable phone. In this manner the convenience of using portable phones is greatly enhanced.
摘要:
Embodiments of the present invention provide for a method, system and article of manufacture for operating vending machines. In general, a plurality of vending machines are nodes of a network. Each node is configured to send, receive and process signals carrying inventory, pricing, reservation and/or refund information. In particular, a first signal is sent to one or more nodes requesting inventory/price information from other nodes. Those nodes carrying the product may reply with a second signal. In this manner, the location of vending machines carrying one or more items specified by a customer may be determined. In another embodiment, vending machine items may be reserved from a remote location. In still another embodiment, vending machines may be configured to provide refunds under controlled conditions. A consumer may request a refund in cases where the consumer was improperly charged for goods are services that were not provided.
摘要:
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.
摘要:
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.
摘要:
A profiler collects profile data according to a defined trigger specification, a defined level specification, and an optional defined skip specification. The profiler begins collecting profile data when the trigger specification is satisfied. The profiler monitors stack frames on a call stack, and collects profile data for the defined level from the current stack frame. A skip specification may also be defined that allows skipping the collecting of profile data for specified jar files, packages, classes, or methods. In this manner, a profiler may collect profile data up to a specified level from the current stack frame while specifically skipping the collection of profile data according to the defined skip specification.
摘要:
An apparatus and method to utilize MQTs in a more efficient manner a computer database to improve database performance and utility. In preferred embodiments, the query optimizer determines if a valid but non-refreshed MQT exists and rewrites a query to operate over the MQT and over the base tables and then joins the results. In preferred embodiments, the query is rewritten to operate over base table results that are stored in a staging table prior to being used to refresh the MQT. In other embodiments, the query is rewritten to operate over the base tables on data records added since the last refresh.
摘要:
An apparatus and method autonomically refreshes an MQT in a computer database to improve database performance and utility. In preferred embodiments, the query optimizer autonomically initiates a refresh of MQT depending on an estimated time for the query to access the base tables. In other preferred embodiments, the query optimizer estimates the time for the query to access the base tables and compares it to the estimated time to refresh the MQT to determine whether to refresh the MQT and run the query over the MQT rather than the base tables.