Abstract: Incrementally updating statistics includes sampling rows from a database column in a database to generate a first sample, sampling a subset of modified rows from the database column after generating the first sample to generate a second sample, determining whether distribution changes occurred to the database column based on the first and second samples, and updating a database statistic about the database column in response to determining that a distribution change exists.

Abstract: One example discloses a database management system that can comprise a memory for storing computer executable instructions and a processing unit for accessing the memory and executing the computer executable instructions. The computer executable instructions can comprise a query data collector to access a query repository table to determine if a first query plan for a first configuration executed on a relational database has a lowest resource cost of execution between the first query plan and a second query plan for a second configuration. The query repository table can include a plurality of query records with annotated query plans, each annotated query plan comprising text sufficient to generate a query plan of a certain form.

Abstract: A method of estimating a number of unique entry counts of an attribute in a database comprises, with a processor: identifying a sample of entries from an attribute database, determining frequencies of a number of input observations of the sample of entries, determining a number of high frequency values of the sample of entries, and estimating a number of unique entry counts of an attribute within the attribute database using a counting Bloom filter and based on the frequencies of the input observations and the high frequency values.

Abstract: Validating a query execution includes determining whether a condition of a query has changed and recompiling the query if the condition has changed.

Abstract: Incrementally updating statistics includes sampling rows from a database column in a database to generate a first sample, sampling a subset of modified rows from the database column after generating the first sample to generate a second sample, determining whether distribution changes occurred to the database column based on the first and second samples, and updating a database statistic about the database column in response to determining that a distribution change exists.

Abstract: An enterprise data warehouse or business intelligence system having a plurality of processors and memory resources. The system includes at least a database server, a workload management system, a query compiler, and a query executor. The database server configured to receive a database query from an application at a database client system. The query compiler configured to prepare the execution plan for the query and compute the number of executive server processes (ESPs) in each ESP layer of the query. The workload management system is configured to generate an affinity value, and the query executor is configured to execute the query. As disclosed herein, placement of the executive server process layers of the query onto processors of the computing system is determined using the affinity value. Other embodiments, aspects and features are also disclosed.

Abstract: Embodiments of the present invention are directed to query-optimization methods and systems that employ risk premiums assigned to database operations in order to increase the robustness and reliability of the evaluation and selection of query-execution plans for executing high-level database queries. Using risk-premium estimates, selection of query-execution plans that include potentially inefficient database operations and inefficient database-operation-execution sequences, often selected by currently available query-optimization methods and systems, are avoided.

Abstract: A method of estimating a number of unique entry counts of an attribute in a database comprises, with a processor: identifying a sample of entries from an attribute database, determining frequencies of a number of input observations of the sample of entries, determining a number of high frequency values of the sample of entries, and estimating a number of unique entry counts of an attribute within the attribute database using a counting Bloom filter and based on the frequencies of the input observations and the high frequency values.

Abstract: A system and method for providing parallel result streams for database queries is provided. The system includes a network including a client, a server, and a database. The client executes an application and sends a query to the server. In response, the server compiles the query to produce a query plan, executes statements in the query plan and sends parallel result streams to the client.

Abstract: There is provided a computer-implemented method of optimizing a query. An exemplary method comprises receiving a first query configured to generate a result set. The query may comprise an operation for an outer table, a first predicate, and a second predicate. The second predicate may comprise a subquery correlated to the operation. Additionally, the first predicate and the second predicate may be disjunctive. The exemplary method also comprises generating a first query tree representing the first query, and generating a second query tree representing a second query. The second query may be configured to generate the result set, and may not comprise the subquery. The exemplary method additionally comprises generating a query plan based on the second query tree.

Abstract: There is provided a computer-implemented method of optimizing a query. An exemplary method comprises determining a maximum cardinality for an operator. The query may comprise the operator. The exemplary method also comprises determining a plurality of potential implementations for the operator. The exemplary method additionally comprises generating a query plan for the query based on the maximum cardinality and the potential implementations.

Abstract: One example discloses a database management system that can comprise a memory for storing computer executable instructions and a processing unit for accessing the memory and executing the computer executable instructions. The computer executable instructions can comprise a query data collector to access a query repository table to determine if a first query plan for a first configuration executed on a relational database has a lowest resource cost of execution between the first query plan and a second query plan for a second configuration. The query repository table can include a plurality of query records with annotated query plans, each annotated query plan comprising text sufficient to generate a query plan of a certain form.

Abstract: There is provided a computer-implemented method of optimizing a query. An exemplary method comprises receiving a first query configured to generate a result set. The query may comprise an operation for an outer table, a first predicate, and a second predicate. The second predicate may comprise a subquery correlated to the operation. Additionally, the first predicate and the second predicate may be disjunctive. The exemplary method also comprises generating a first query tree representing the first query, and generating a second query tree representing a second query. The second query may be configured to generate the result set, and may not comprise the subquery. The exemplary method additionally comprises generating a query plan based on the second query tree.

Abstract: There is provided a computer-implemented method of optimizing a query. An exemplary method comprises determining a maximum cardinality for an operator. The query may comprise the operator. The exemplary method also comprises determining a plurality of potential implementations for the operator. The exemplary method additionally comprises generating a query plan for the query based on the maximum cardinality and the potential implementations.

Abstract: The disclosed embodiments relate to a system for refreshing a table to produce a refreshed table. The system may include a refresh log that may contain a plurality of entries that each comprise an epoch identifier. The system may also include a refresh manager that may be adapted to perform a refresh operation on the table using entries that have corresponding epoch identifiers.

Abstract: A system and method for providing parallel result streams for database queries is provided. The system includes a network including a client, a server, and a database. The client executes an application and sends a query to the server. In response, the server compiles the query to produce a query plan, executes statements in the query plan and sends parallel result streams to the client.

Abstract: Embodiments of the present invention are directed to query-optimization methods and systems that employ risk premiums assigned to database operations in order to increase the robustness and reliability of the evaluation and selection of query-execution plans for executing high-level database queries. Using risk-premium estimates, selection of query-execution plans that include potentially inefficient database operations and inefficient database-operation-execution sequences, often selected by currently available query-optimization methods and systems, are avoided.

Abstract: Systems and methods to indicate whether to store a database query language module in a local directory or a global directory are disclosed. An application program can be created once, tested once, and deployed in separate environments. The database query language modules can be shared among a group of application programs running in a common environment. Separate query language modules can be maintained for each environment.

Abstract: An apparatus, system, and method are disclosed for provisioning database resource within a grid database system. The apparatus comprises an analysis module and a provision module. The analysis module analyzes a data query stream from an application to a database instance and determines that the data query stream exhibits a predetermined performance attribute. The provision module provisions a database resource in response to a determination that the data query stream exhibits the predetermined performance attribute. The provisioned database resource may be a database instance, a database server, or a cache. The provisioning of the new database resource advantageously is substantially transparent to a client on the database system.

Abstract: An enterprise data warehouse or business intelligence system having a plurality of processors and memory resources. The system includes at least a database server, a workload management system, a query compiler, and a query executor. The database server configured to receive a database query from an application at a database client system. The query compiler configured to prepare the execution plan for the query and compute the number of executive server processes (ESPs) in each ESP layer of the query. The workload management system is configured to generate an affinity value, and the query executor is configured to execute the query. As disclosed herein, placement of the executive server process layers of the query onto processors of the computing system is determined using the affinity value. Other embodiments, aspects and features are also disclosed.