Abstract: Query optimizer accuracy is tested by measuring the actual execution times on a database of each of a plurality of alternative query plans for each of a plurality of queries, first ranking the plans by the actual execution times, then ranking the plans by estimated execution times, and correlating the two rankings by computing a rank correlation metric. The rank correlation metric is normalized so that different optimizers can be objectively compared.

Abstract: A minimal portable executable bug repro contains the inputs to a query optimizer, metadata, statistics, process and thread specific information such as stack traces, and state at the time of a crash necessary to reproduce the problem. Objects register with a handler prior to use, and the handler pre-allocates sufficient buffer space to store each. Upon a crash, the handler requests each object to serialize itself into the pre-allocated space, and captures the relevant information in a transactionally consistent way. The executable file may be loaded onto a debugging system, and the execution sequence replayed to analyze the problem.

Abstract: A system and method for distributed query processing may compile and optimize query plans for incoming query requests independent of hardware configurations and/or physical locations of data partitions in a distributed storage system (e.g., a data grid). The query plan may be divided into segments, and each segment may be instantiated on a remote query processing node of the distributed system by a query coordinator node according to metadata accessed at runtime by remote sub-query operators in the query plan. The metadata may include an indication of the physical locations of data partitions in the system and may be stored on one or more of the query processing nodes. The remote query processing nodes may execute the query plan segments and return results to the requestor. Cached query plans may be re-executed without recompilation, according to current metadata, even in the event of a node failure or data partition move.

Abstract: Systems and methods are provided to increase the scalability of subscriptions in an electronic database environment. In an illustrative implementation, a computing application comprises at least one instruction set to cooperate with a data environment to optimize the processing of subscriptions by the data environment when communicating with cooperating services and/or applications. In operation, a subscription is identified. A subscription template is created for the subscription and the subscription template is parameterized to create a parameter table containing parameters (e.g. subscription constants). A join is then performed between the parameters of the parameter table and the parameterized subscription templates to generate application and/or service data required by the cooperating services and/or applications. The data is then processed by the applications and/or services.

Abstract: Indexed views or materialized views are used as a secondary index on a base table with multi-valued attributes. This provides for using the index to search in the nested data. Moreover, indexing is provided on the result of an unnest operation. Indexing a view on the result of an unnesting operation provides the ability to index the contents of a nested collection. One such unnesting operation is “cross apply unnest”. This provides additional options for a query execution plan, leading to a more optimized query. A back-join is provided from the indexed view to the base table to allow fields from the base table that are not present in the indexed view to be included in a result of a query on the table which is processed using the indexed view as an access path. This provides a means of including columns in the query result that are not in the indexed view but are in the base table.

Abstract: Indexed views or materialized views are used as a secondary index on a base table with multi-valued attributes. This provides for using the index to search in the nested data. Moreover, indexing is provided on the result of an unnest operation. Indexing a view on the result of an unnesting operation provides the ability to index the contents of a nested collection. One such unnesting operation is “cross apply unnest”. This provides additional options for a query execution plan, leading to a more optimized query. A back-join is provided from the indexed view to the base table to allow fields from the base table that are not present in the indexed view to be included in a result of a query on the table which is processed using the indexed view as an access path. This provides a means of including columns in the query result that are not in the indexed view but are in the base table.

Abstract: Indexed views or materialized views are used as a secondary index on a base table with multi-valued attributes. This provides for using the index to search in the nested data. Moreover, indexing is provided on the result of an unnest operation. Indexing a view on the result of an unnesting operation provides the ability to index the contents of a nested collection. One such unnesting operation is “cross apply unnest”. This provides additional options for a query execution plan, leading to a more optimized query. A back-join is provided from the indexed view to the base table to allow fields from the base table that are not present in the indexed view to be included in a result of a query on the table which is processed using the indexed view as an access path. This provides a means of including columns in the query result that are not in the indexed view but are in the base table.

Abstract: Indexed views or materialized views are used as a secondary index on a base table with multi-valued attributes. This provides for using the index to search in the nested data. Moreover, indexing is provided on the result of an unnest operation. Indexing a view on the result of an unnesting operation provides the ability to index the contents of a nested collection. One such unnesting operation is “cross apply unnest”. This provides additional options for a query execution plan, leading to a more optimized query. A back-join is provided from the indexed view to the base table to allow fields from the base table that are not present in the indexed view to be included in a result of a query on the table which is processed using the indexed view as an access path. This provides a means of including columns in the query result that are not in the indexed view but are in the base table.

Abstract: A client submits a subscription to a database specifying selected data within a data set. A subscription plan is generated based on the subscription. A query is submitted to the database changing selected data within the data set. A query plan is generated based on the query. The subscription is matched to the query based on the data set, and the query plan is supplemented with the subscription plan to generate a notification of the change to the client.

Abstract: During query execution, statistics associated with expressions are observed. Such observed statistics preferably include the cardinality of each expression. The observed statistics are submitted to an expression manager as feedback from the executed query. The statistics are preferably stored for use in estimating the cardinality of execution plans for future queries.

Abstract: Systems and methods are provided to increase the scalability of subscriptions in an electronic database environment. In an illustrative implementation, a computing application comprises at least one instruction set to cooperate with a data environment to optimize the processing of subscriptions by the data environment when communicating with cooperating services and/or applications. In operation, a subscription is identified. A subscription template is created for the subscription and the subscription template is parameterized to create a parameter table containing parameters (e.g. subscription constants). A join is then performed between the parameters of the parameter table and the parameterized subscription templates to generate application and/or service data required by the cooperating services and/or applications. The data is then processed by the applications and/or services.

Abstract: A client submits a subscription to a database specifying selected data within a data set. A subscription plan is generated based on the subscription. A query is submitted to the database changing selected data within the data set. A query plan is generated based on the query. The subscription is matched to the query based on the data set, and the query plan is supplemented with the subscription plan to generate a notification of the change to the client.

Abstract: During query execution, statistics associated with expressions are observed. Such observed statistics preferably include the cardinality of each expression. The observed statistics are submitted to an expression manager as feedback from the executed query. The statistics are preferably stored for use in estimating the cardinality of execution plans for future queries.

Abstract: The present invention relates to systems and methods for saving results generated from database queries such as raw data, objects, queryable data sets, full or partial web responses, in memory for current and subsequent utilization and invaliding the saved results when they become inconsistent to mitigate employing inconsistent results. The saved results can be employed by one or more components and are typically utilized when a subsequent query would return substantially similar results. Thus, the system and methods mitigate performing substantially redundant queries that can reduce performance and consume resources. When a database change occurs that affect the consistency of the saved results and/or expiration period lapses, an invalidation message can be transmitted, wherein the message is employed to invalidate the saved results. Thus, the systems and methods mitigate employing inconsistent saved results.