Abstract: A mechanism of updating query results for a graph linking data in a computer system is disclosed. Results of the query on the graph linking data are received along with a change to the graph. The change to the graph is determined to be localizable or relatively bounded. Based on the determination of the localizable or relatively bounded change to the graph, the results of the query are updated based on the change to the graph without determining updated results of the query over the graph. This is accomplished by discovering nodes that are affected by the change to the graph, updating data associated with the affected nodes, and applying the updated data to the results of the query.

Abstract: A mechanism for rewriting a bounded query onto a view is disclosed. A query, access constraints, and cached view(s) are obtained. The cached view(s) contain results of the query as applied to a dataset stored in a database. A query rewriting plan is generated by adding a fetch from query operation to the plan when a rewritten query variable can be fetched from a query constant. A fetch from database operation is added to the plan when a rewritten query variable can be fetched as a query variable that obtains bounded data from the database. An access view operation is added to the plan when a rewritten query variable can be fetched from the cached view. The query rewriting plan is executed to fetch retrieved data. The query is executed on the retrieved data to determine updated results to the query without reapplying the query to the dataset.

Abstract: A system (and associated method) includes a processor which determines a performance metric ratio of a performance metric of a second type of server relative to a performance metric of a first server type for each of multiple sizes of multiple benchmark datasets to thereby determine a plurality of performance metric ratio values. The processor also determines an interpolation function for the plurality of performance metric ratio values usable to compute interpolation performance metric ratios of the second type of server relative to the first type of server for dataset sizes other than the first plurality of sizes. Given a second dataset, the processor determines an amount of the second dataset to provide to each of the respective server types using the interpolation function. The processor configures a load balancer based on the amount of the second dataset determined for each type of server.

Abstract: A system (and associated method) includes a processor which determines a performance metric ratio of a performance metric of a second type of server relative to a performance metric of a first server type for each of multiple sizes of multiple benchmark datasets to thereby determine a plurality of performance metric ratio values. The processor also determines an interpolation function for the plurality of performance metric ratio values usable to compute interpolation performance metric ratios of the second type of server relative to the first type of server for dataset sizes other than the first plurality of sizes. Given a second dataset, the processor determines an amount of the second dataset to provide to each of the respective server types using the interpolation function. The processor configures a load balancer based on the amount of the second dataset determined for each type of server.

Abstract: A mechanism for rewriting a bounded query onto a view is disclosed. A query, access constraints, and cached view(s) are obtained. The cached view(s) contain results of the query as applied to a dataset stored in a database. A query rewriting plan is generated by adding a fetch from query operation to the plan when a rewritten query variable can be fetched from a query constant. A fetch from database operation is added to the plan when a rewritten query variable can be fetched as a query variable that obtains bounded data from the database. An access view operation is added to the plan when a rewritten query variable can be fetched from the cached view. The query rewriting plan is executed to fetch retrieved data. The query is executed on the retrieved data to determine updated results to the query without reapplying the query to the dataset.

Abstract: A mechanism of updating query results for a graph linking data in a computer system is disclosed. Results of the query on the graph linking data are received along with a change to the graph. The change to the graph is determined to be localizable or relatively bounded. Based on the determination of the localizable or relatively bounded change to the graph, the results of the query are updated based on the change to the graph without determining updated results of the query over the graph. This is accomplished by discovering nodes that are affected by the change to the graph, updating data associated with the affected nodes, and applying the updated data to the results of the query.

Abstract: System and method for storing statistical data of records stored in a distributed file system. In one aspect a statistical data block is allocated in a memory of a data node for storing statistical data of records stored in a storage disk of the data node. Each data block of the plurality of data blocks in the data node has a respective entry in the statistical data block, which is collocated with data blocks on the data node. Statistical data of records stored in the distributed file system are collected, and written to statistical data block in the memory of the data node.

Abstract: Techniques are provided that determine that a query includes at least one subquery that may be correlated or decorrelated. An internal representation of the query that represents the subquery in both correlated and decorrelated form is generated, wherein the internal representation includes at least one virtual table.

Abstract: Techniques are provided that determine that a query includes at least one subquery that may be correlated or decorrelated. An internal representation of the query that represents the subquery in both correlated and decorrelated form is generated, wherein the internal representation includes at least one virtual table.

Abstract: Techniques are provided that determine that a query includes at least one subquery that may be correlated or decorrelated. An internal representation of the query that represents the subquery in both correlated and decorrelated form is generated, wherein the internal representation includes at least one virtual table.

Abstract: A method generates hierarchical path index keys for single and multiple indexes with one scan of a document. Each data node of the document is scanned and matches to query nodes are identified. A data node matches a query node if the three conditions hold: if it is not the root step, there is a match for the query node in the previous step of the query; the data node matches the query node of the current step; and the edges of the data and query nodes match. A sub-tree of a data node can be skipped if the data node is not matched and its level is less than the fixed levels of the query. The matched data node is then placed in the match stacks corresponding to the match query nodes. The method uses transitivity properties among matching units to reduce the number of states that need to be tracked and to improve the evaluation of path expressions significantly.

Abstract: Techniques are provided that determine that a query includes at least one subquery that may be correlated or decorrelated. An internal representation of the query that represents the subquery in both correlated and decorrelated form is generated, wherein the internal representation includes at least one virtual table.

Abstract: A method generates hierarchical path index keys for single and multiple indexes with one scan of a document. Each data node of the document is scanned and matches to query nodes are identified. A data node matches a query node if the three conditions hold: if it is not the root step, there is a match for the query node in the previous step of the query; the data node matches the query node of the current step; and the edges of the data and query nodes match. A sub-tree of a data node can be skipped if the data node is not matched and its level is less than the fixed levels of the query. The matched data node is then placed in the match stacks corresponding to the match query nodes. The method uses transitivity properties among matching units to reduce the number of states that need to be tracked and to improve the evaluation of path expressions significantly.