Abstract:
In an example, a transitive local predicates may be inferred across multiple joins, wherein the multiple outer joins include multiple outer joins. A query connecting tables by the multiple joins is analyzed. A local predicate may then be identified from the analyzed query and may be determined to be either a where-clause local predicate or an on-clause local predicate. Accordingly, a transitive local predicate may be inferred across a selection of the tables based on the determination.
Abstract:
Techniques are described herein for executing queries with a recursive clause using a plurality of processes that execute database operations in parallel. Each process of the plurality of processes either generate or are assigned a segment that is part of a temporary table. For each iteration of the recursive query, work granules are divided up and assigned to each of the plurality of processes. As each respective process produces a portion of a result set for a given iteration, that process appends said portion of the result set to the respective segment that the respective process manages. Each slave process then publishes, to one or more sources, a reference to the newly generated results. During the next iteration, any slave process may access any of the data from the previous iteration.
Abstract:
A hybrid approach for evaluating expressions in database management systems is described herein. For each expression in an execution location (XL), an execution strategy is selected. The strategies considered are lazy, lazy with memoization, eager, and eager with memoization. The execution strategies are assigned in a way that minimizes the estimated cost of evaluation.
Abstract:
A first query and a second query are received. The first query and the second query are evaluated and, based upon the evaluating, identifying first time series data required to fulfill the first query and second time series data required to fulfill the second query. An extent of overlap of the first time series data and the second time series data is determined. When the extent of overlap exceeds a predetermined threshold, the overlapping data is retrieved from a plurality of data storage devices in parallel, the data retrieved across all of the plurality of storage devices via a single read operation.
Abstract:
The embodiments of the invention provide a method, program storage device, etc. for automated and dynamic management of query views for database workloads. More specifically, a method begins by executing queries, which includes accessing a set of data tables for each of the queries. During the executing of the queries, the method accesses a required data table from a cache if the required data table is present in the cache and creates the required data table if the required data table is not present in the cache. The accessing of the required data table from the cache has a lower processing cost than accessing the required data table from a base table. Also during the executing of the queries, created data tables are stored in the cache, wherein one or more of the created data tables are removed from the cache when the cache becomes full.
Abstract:
A method of resolving a plurality of database queries. The method includes accumulating a plurality of queries, determining overlapping portions of the queries that relate to one or more common data attributes, resolving at least two of the determined overlapping portions of the queries together, and preparing responses to the queries based on the resolution of the at least two overlapping portions.
Abstract:
A data management system and method. The system is adapted to analyze a plurality of data queries and provide a metric with respect thereto. The system then orders the queries based on the metric to improve a performance parameter of the system or estimate an execution time with respect to the query. In a more specific implementation, the system includes code for analyzing a signature of each of the queries, comparing the signature to a calibrated signature and providing a signature score in response thereto. The system further includes code for estimating an execution time of at least one of the queries. The signature may be a cluster of statements in an appropriate language such as SQL (standard query language). As an alternative, the signature maybe a set of features extracted from a plurality of statements.
Abstract:
A query resolving system, which includes an input interface adapted to receive queries, a data identifier which is adapted to convert the received queries into query fragments and to identify which data segments are required in order to resolve the query fragments, one or more execution blocks adapted to resolve query fragments, a data storage unit which stores a plurality of data segments, at least one high speed link which connects the data storage unit to the one or more execution blocks, and a data sweeping unit which selectively sweeps data segments over the at least one high speed link to the one or more execution blocks, responsive to the identification of the data identifier.
Abstract:
Disclosed is a method for determining database queries to be sent by an analytical server to a Relational Database Monitoring System (RDBMS) by using hierarchical level metadata to describe the various structures within the database.