Abstract: A system for retrieving stored data and/or index pages, receives a database request, generates an access plan for the database request for accessing data rows and/or index entries according to the statement, and generates a priming process by selecting a set of data and/or index pages. The set of data and/or index pages is a super-set or the exact set of the pages needed for accessing data rows and/or index entries according to the access plan. The present system retrieves the data and/or index pages of the set before executing the database request according to the access plan. The execution of the database request is performed by scanning the index and data pages preloaded into the cache. This reduces the number of necessary disk reads during execution.

Abstract: According to an embodiment of the present invention, a method for reorganizing a source index tree of a database table resulting in a target index tree of the database table is provided. A backup process reads source leaf pages of the source index tree in a logical order defined by a sequence of index keys. The logical order can be different from a physical order of the source leaf pages defined by a sequence of respective storage locations. The backup process constructs target leaf pages of the target index tree maintaining the logical order. A restore process constructs target non-leaf pages of the target index tree based on the distribution of the index keys among the constructed leaf pages and stores the target leaf and non-leaf pages.

Abstract: According to one embodiment of the present invention, a method for identifying relevant database indexes is provided. According to one embodiment of the present invention, a method includes determining the importance of a particular database transaction and storing an index name related to the transaction along with an indicator of the importance. A database transaction is initiated and the importance indicator is received in an index advisor. The index advisor then makes an index recommendation based on the index importance.

Abstract: The present solution addresses the need to carry out reorganization of a database storage. A statistics-based reorganization check procedure is performed on at least first database tables and indexes, resulting in a preliminary reorganization recommendation. Information on workload on tables and indexes of said database storage is received. Based on the information on workload and the preliminary reorganization recommendation, it is decided whether to carry out reorganization of the database storage in accordance with the preliminary reorganization recommendation.

Abstract: The present system indexes a plurality of entries in a database that contains a database table having a base index. As a recent row is inserted in the database table, an index increment is generated based on the inserted row. Preferably, the index increment is smaller in size than the base index because it is recently generated. The smaller size of the index increment facilitates the management of the index increment. An index entry associated with the inserted row is added to the index increment, and the index increment is merged with the base index.

Abstract: The present invention proposes enhancing the access path selection process by storing the relevant frequency distribution and the host variables values used for selecting the access path together with the corresponding access path executable. This way, the host variables impact to the access path can be inexpensively assessed and the re-optimization triggered only if necessary.

Abstract: A method of searching a data page in a table space of a database for inserting a data record to a first table, wherein the table space comprises space map pages and sets of data pages, wherein each space map page comprises information about the available storage space of one set of data pages, wherein each space map page and the corresponding set of data pages is further assigned to a table range for each table to which at least one data page in the set of data pages belongs to, wherein the database further comprises a clustering index for the first table in the database management system, wherein the database management system comprises a space usage information database, and wherein the space usage information database holds space usage information for each table range.

Abstract: A method and system for preventing redundant indexes in a database management system (DBMS). A received create-index command specifies a new index to be created for retrieving data from a table created by the DBMS and a redundancy check to be performed for the new index in conjunction with an action parameter in the create-index command. If the action parameter includes a REPORT value, each redundant index is stored and/or displayed and the new index is created. If the action parameter includes a PREVENT value and an existing index is redundant in view of the new index and the new index is not redundant in view of the existing index, the existing index is deleted and the new index is created. If the action parameter includes a PREVENT value and the new index is redundant in view of an existing index, the new index is not created.

Abstract: Presented is a method to perform a query to retrieve data from a database that is part of a computer system comprising a Data-Base Management System (DBMS) with an optimizer. A Query Execution Plan (QEP) is generated for the query. The QEP is assessed by considering statistical values about previous executions of the query according to the QEP to decide whether to choose the QEP or to generate a new QEP. Furthermore, the statistical values on previous executions of the query are exploited during query optimization. The query is executed according to the chosen QEP. For optimizing the execution of future queries, statistical values about the execution of the query are collected during execution.

Abstract: The present solution addresses the need to carry out reorganization of a database storage. A statistics-based reorganization check procedure is performed on at least first database tables and indexes, resulting in a preliminary reorganization recommendation. Information on workload on tables and indexes of said database storage is received. Based on the information on workload and the preliminary reorganization recommendation, it is decided whether to carry out reorganization of the database storage in accordance with the preliminary reorganization recommendation.

Abstract: A method for performing a system level backup of a log-ahead database management system (DBMS) without suspending updates by application programs is described. The DBMS comprises a database mainline system, a backup utility and a restore utility. The data and log records are stored on separate storage volumes. Log records are written to identify objects that require special handling during the point-in-time recovery. The database engine operates normally during a backup except for suspending actions that would alter the file system catalog or write updates across a storage volume boundary; and by freezing the REDO log point in its checkpoint information. The backup utility copies the data volumes first and optionally the log volumes second while updates are allowed. The resulting inconsistencies are resolved either during a DBMS restart or during a point-in-time (PIT) recovery performed by the restore utility.

Abstract: According to the present invention a method and a system is provided for establishing synchronized recovery log points in an infrastructure comprising at least a first database management system and a second database management system, whereby recovery log files are written and log points are created separately for each database management system. Firstly, log write of all database management systems is suspended, then, the corresponding log points for each database management system forming a global log point are recorded and log writes of all database management systems are resumed.

Abstract: The present invention proposes enhancing the access path selection process by storing the relevant frequency distribution and the host variables values used for selecting the access path together with the corresponding access path executable. This way, the host variables impact to the access path can be inexpensively assessed and the re-optimization triggered only if necessary.

Abstract: The present invention proposes enhancing the access path selection process by storing the relevant frequency distribution and the host variables values used for selecting the access path together with the corresponding access path executable. This way, the host variables impact to the access path can be inexpensively assessed and the re-optimization triggered only if necessary.

Abstract: According to the method for establishing a log point an information technology infrastructure is provided. Transactions are performed by at least two database units of the information technology infrastructure. Then, “suspending prepare to commit”-requests are sent from said coordinating device to said database units. The log writes of all database units are suspended and recorded, whereas these log points form a global log point. Finally the log writes of all database units and all the suspended transactions are resumed.

Abstract: A method of searching a data page in a table space of a database for inserting a data record to a first table, wherein the table space comprises space map pages and sets of data pages, wherein each space map page comprises information about the available storage space of one set of data pages, wherein each space map page and the corresponding set of data pages is further assigned to a table range for each table to which at least one data page in the set of data pages belongs to, wherein the database further comprises a clustering index for the first table in the database management system, wherein the database management system comprises a space usage information database, and wherein the space usage information database holds space usage information for each table range.

Abstract: A method for tuning a database system is disclosed. A tuning strategy is received comprising a first procedure to determine a suggested tuning action, and a second procedure to measure performance of the database system. The suggested tuning action is determined and pre-action performance measured according to the respective procedures. Undo information that indicates how to undo the database system state change of the suggested tuning action is recorded in a database system state history. After executing the suggested tuning action, post-action database system performance is measured according to the second procedure. When the post-action performance is lower than the pre-action performance, the database system state change is undone using the undo information. Embodiments enabling to create new tuning strategies, downloading existing tuning strategies, sharing own tuning strategies and changing existing tuning strategies are disclosed as well.

Abstract: A computer program product provides accurate statistics in real time. These statistics can be used to determine if a table space in a database management system (DBMS) requires maintenance operations such as reorganization, back up, fresh access path statistics, and/or larger disk space allocation. The DBMS maintains a set of values that provide indications of whether that operation is due on that object. The indicators are asynchronously externalized in dedicated database tables either periodically in user-specified intervals or at some predefined event such as stopping the database. When the user performs a database administration operation, the database management system resets the associated indicators, and reports objects that are in an exception state based on the indicators collected as described for each operation.

Abstract: A system for retrieving stored data and/or index pages, receives a database request, generates an access plan for the database request for accessing data rows and/or index entries according to the statement, and generates a priming process by selecting a set of data and/or index pages. The set of data and/or index pages is a super-set or the exact set of the pages needed for accessing data rows and/or index entries according to the access plan. The present system retrieves the data and/or index pages of the set before executing the database request according to the access plan. The execution of the database request is performed by scanning the index and data pages preloaded into the cache. This reduces the number of necessary disk reads during execution.

Abstract: Embodiments of the present invention provide a “look-ahead” form prefetch. Look-ahead prefetch may utilize a look-ahead queue to prefetch multiple pages asynchronously. The look-ahead queue may hold a plurality of search keys that are related to a transaction. When accessing a table, an index manager may retrieve the table's index and scan the index based on the search keys from the look-ahead queue to find the RIDs in the table that match the search keys. The index manager may then accumulate these RIDs into a prefetch list. A prefetch manager may read the prefetch list, determine locations for the pages of the table that contain the records identified by the RIDs, and dispatch prefetch tasks to the appropriate storage device for these pages.