Abstract: In an approach to determining an access method for a partition in a partition table, a computer receives a query and determines if there is a partition table utilized by the query. When there is a partition table utilized by the query, then the computer determines that a partition in the partition table meets the plurality of conditions of the query. The computer collects a plurality of partition level statistics for the partition that meets the plurality of conditions of the query. Additionally, the computer determines, based, at least in part, on the plurality of partition level statistics, a cost for one or more access methods for the partition that meets the plurality of conditions of the query. Furthermore, the computer determines, based, at least in part, on the cost for each access method, an access method for the partition that meets the plurality of conditions of the query.

Abstract: In an approach to determining an access method for a partition in a partition table, a computer receives a query and determines if there is a partition table utilized by the query. When there is a partition table utilized by the query, then the computer determines that a partition in the partition table meets the plurality of conditions of the query. The computer collects a plurality of partition level statistics for the partition that meets the plurality of conditions of the query. Additionally, the computer determines, based, at least in part, on the plurality of partition level statistics, a cost for one or more access methods for the partition that meets the plurality of conditions of the query. Furthermore, the computer determines, based, at least in part, on the cost for each access method, an access method for the partition that meets the plurality of conditions of the query.

Abstract: A computer-implemented method includes identifying one or more database modification statements and identifying one or more operational unit indicators. The one or more operation unit indicators are caused to be generated by the one or more database modification statements. An anticipated operational size is determined. The anticipated operational size is an estimated total number of the one or more operational unit indicators. An anticipated operational throughput rate is determined. The anticipated operational throughput rate is a rate at which the operational unit indicators are expected to be generated. An anticipated total execution time of the one or more database modification statements is determined based on the anticipated operational size and the anticipated operational throughput rate. A corresponding computer program product and computer system are also disclosed.

Abstract: A computer-implemented method includes identifying one or more database modification statements and identifying one or more operational unit indicators. The one or more operation unit indicators are caused to be generated by the one or more database modification statements. An anticipated operational size is determined. The anticipated operational size is an estimated total number of the one or more operational unit indicators. An anticipated operational throughput rate is determined. The anticipated operational throughput rate is a rate at which the operational unit indicators are expected to be generated. An anticipated total execution time of the one or more database modification statements is determined based on the anticipated operational size and the anticipated operational throughput rate. A corresponding computer program product and computer system are also disclosed.

Abstract: A computer maps a literal in a database query to a digital representation, wherein the database query comprises a predicate, the literal is a part of the predicate, and the digital representation is predetermined based at least in part on external statistical data. The computer estimates a filter factor for the predicate based at least in part on the digital representation and compressed statistical data, wherein the compressed statistical data are prepared at least in part from the external statistical data.

Abstract: In an approach to determining an access method for a partition in a partition table, a computer receives a query and determines if there is a partition table utilized by the query. When there is a partition table utilized by the query, then the computer determines that a partition in the partition table meets the plurality of conditions of the query. The computer collects a plurality of partition level statistics for the partition that meets the plurality of conditions of the query. Additionally, the computer determines, based, at least in part, on the plurality of partition level statistics, a cost for one or more access methods for the partition that meets the plurality of conditions of the query. Furthermore, the computer determines, based, at least in part, on the cost for each access method, an access method for the partition that meets the plurality of conditions of the query.

Abstract: A computer maps a literal in a database query to a digital representation, wherein the database query comprises a predicate, the literal is a part of the predicate, and the digital representation is predetermined based at least in part on external statistical data. The computer estimates a filter factor for the predicate based at least in part on the digital representation and compressed statistical data, wherein the compressed statistical data are prepared at least in part from the external statistical data.

Abstract: In an approach to determining an access method for a partition in a partition table, a computer receives a query and determines if there is a partition table utilized by the query. When there is a partition table utilized by the query, then the computer determines that a partition in the partition table meets the plurality of conditions of the query. The computer collects a plurality of partition level statistics for the partition that meets the plurality of conditions of the query. Additionally, the computer determines, based, at least in part, on the plurality of partition level statistics, a cost for one or more access methods for the partition that meets the plurality of conditions of the query. Furthermore, the computer determines, based, at least in part, on the cost for each access method, an access method for the partition that meets the plurality of conditions of the query.

Abstract: A system for transferring data from a Relational Database Management System (“RDBMS”) to a big data platform and methods for making and using the same. The system can acquire a partitioning execution scheme of a selected table from the RDBMS and submitting partitioned queries from the big data platform to each mapper of partitions. The partitioned queries are generated based on the partitioning execution scheme. The partitioning execution scheme can be acquired by submitting a query explain request to an optimizer of the RDBMS to generating a parallel query plan. The partitioning execution scheme can also be acquired by querying statistics from a statistics catalog of the RDBMS or by user inputs. The system can use RDBMS capabilities and statistics for parallel data fetching. Thereby, the system can increase efficiency of the fetching and can avoid straggling when target data is not evenly distributed and can avoid table query-in-serial.

Abstract: An integrated data processing system with two-tier data caching system and techniques for use thereof in a hybrid RDBMS and BDS computing environment are provided. In one aspect, the system is RDBMS-centric and uses two caches, one on the RDBMS side (1st tier) and the other on the BDS side (2nd tier). In another aspect, a DRDA wrapper on the BDS side enables the RDBMS to communicate with the BDS as if the BDS is another RDBMS. This is advantageous because the RDBMS already supports the DRDA protocol standard. In yet another aspect, the DRDA wrapper performs the data transformation needed when transferring cached objects between the RDBMS cache and BDS cache because RDBMS and BDS save data objects in different formats. This is advantageous because it offloads the computation from RDBMS to BDS therefore reducing the performance impact on RDBMS for its normal query and transaction processing.

Abstract: A method and system for database indexing, wherein a database index comprises at least one index include. The method and system includes obtaining the number of executions of each of a plurality of Structured Query Language (SQL) statements within a certain time period, respectively, wherein the plurality of SQL statements use the database index. For each of the at least one index include, calculating a number of hits of the index include according to the number of executions of each of the plurality of SQL statements. Further, obtaining a length of the index include, and calculating a hit frequency of the index include by using the number of hits and the length of the index include. The hit frequency equals the number of hits divided by the length.

Abstract: A computer-implemented method includes receiving a batch processing job. The method identifies multiple access paths for the batch processing job. The method determines one or more runtime costs for each of the multiple access paths. The method determines whether the batch processing job includes comparable access paths. The method responds to the batch processing job not including comparable access paths by receiving a query and selecting a desired access, based on the one or more runtime costs. The method responds to the batch processing job including comparable access paths by determining one or more context costs for each of the one or more access paths, receiving a query, identifying a context for the query, and selecting a desired access path for the query. The desired access path is based on the one or more runtime costs, the one or more context costs, and the context for the query.

Abstract: In an approach to determining an access method for a partition in a partition table, a computer receives a query and determines if there is a partition table utilized by the query. When there is a partition table utilized by the query, then the computer determines that a partition in the partition table meets the plurality of conditions of the query. The computer collects a plurality of partition level statistics for the partition that meets the plurality of conditions of the query. Additionally, the computer determines, based, at least in part, on the plurality of partition level statistics, a cost for one or more access methods for the partition that meets the plurality of conditions of the query. Furthermore, the computer determines, based, at least in part, on the cost for each access method, an access method for the partition that meets the plurality of conditions of the query.

Abstract: In an approach to determining an access method for a partition in a partition table, a computer receives a query and determines if there is a partition table utilized by the query. When there is a partition table utilized by the query, then the computer determines that a partition in the partition table meets the plurality of conditions of the query. The computer collects a plurality of partition level statistics for the partition that meets the plurality of conditions of the query. Additionally, the computer determines, based, at least in part, on the plurality of partition level statistics, a cost for one or more access methods for the partition that meets the plurality of conditions of the query. Furthermore, the computer determines, based, at least in part, on the cost for each access method, an access method for the partition that meets the plurality of conditions of the query.

Abstract: A computer-implemented method includes receiving a batch processing job. The method identifies multiple access paths for the batch processing job. The method determines one or more runtime costs for each of the multiple access paths. The method determines whether the batch processing job includes comparable access paths. The method responds to the batch processing job not including comparable access paths by receiving a query and selecting a desired access, based on the one or more runtime costs. The method responds to the batch processing job including comparable access paths by determining one or more context costs for each of the one or more access paths, receiving a query, identifying a context for the query, and selecting a desired access path for the query. The desired access path is based on the one or more runtime costs, the one or more context costs, and the context for the query.

Abstract: A computer-implemented method includes receiving a batch processing job. The method identifies multiple access paths for the batch processing job. The method determines one or more runtime costs for each of the multiple access paths. The method determines whether the batch processing job includes comparable access paths. The method responds to the batch processing job not including comparable access paths by receiving a query and selecting a desired access, based on the one or more runtime costs. The method responds to the batch processing job including comparable access paths by determining one or more context costs for each of the one or more access paths, receiving a query, identifying a context for the query, and selecting a desired access path for the query. The desired access path is based on the one or more runtime costs, the one or more context costs, and the context for the query.

Abstract: Disclosed aspects relate to query processing management in a database management system (DBMS). The DBMS may detect that a query has a set of subqueries. The DBMS may detect that the set of subqueries indicates a set of data structures. A lead data structure may be selected from the set of data structures using a selection criterion. A set of input columns may be identified from the lead data structure of the set of data structures. A set of output columns may be identified from the set of data structures other than the lead data structure. A hash data structure may be constructed using the set of input columns and the set of output columns. A cache may be built based on the hash data structure.

Abstract: In an approach to determining an access method for a partition in a partition table, a computer receives a query and determines if there is a partition table utilized by the query. When there is a partition table utilized by the query, then the computer determines that a partition in the partition table meets the plurality of conditions of the query. The computer collects a plurality of partition level statistics for the partition that meets the plurality of conditions of the query. Additionally, the computer determines, based, at least in part, on the plurality of partition level statistics, a cost for one or more access methods for the partition that meets the plurality of conditions of the query. Furthermore, the computer determines, based, at least in part, on the cost for each access method, an access method for the partition that meets the plurality of conditions of the query.

Abstract: Aspects of the present disclosure relate to an approach for generating query execution plans for a database query. A computer-implemented method comprises determining whether a size of a file to be generated during execution of a database query is variable in response to obtaining the database query. The method further comprises determining a plurality of ranges for the size of the file in response to determining that the size of the file is variable. The method further comprises generating a plurality of query execution plans corresponding to the plurality of ranges. Accordingly, a plurality of query execution plans corresponding to different file sizes can be generated for the database query, and an efficient and cost effective query execution plan may be selected based on the actual file size during the execution of the database query.

Abstract: A computer-implemented method includes identifying a query, including one or more predicates and one or more branches, wherein one or more branches includes one or more legs. The computer-implemented method further includes, for each branch, in parallel: determining a risk, determining a return row threshold, estimating a number of return rows; terminating access if the return rows exceed the threshold. The computer-implemented method further includes, for each leg, in parallel: determining a leg return row threshold; accessing the leg; fetching one or more return rows into one or more leg return row pages; terminating access if the return rows exceed the threshold; intersecting one or more leg return row pages into one or more intersected leg return row pages; and applying the one or more predicates to the one or more intersected leg return row pages. The method may be embodied in a corresponding computer system or computer program product.