摘要:
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.
摘要:
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.
摘要:
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.
摘要:
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.
摘要:
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.
摘要:
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.
摘要:
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.
摘要:
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.
摘要:
Methods and apparatus, including computer program products, for maintaining a set of indexes in a database management system (DBMS) having at least one table. A current, stale or deferred status is defined for at least a part of the indexes, resulting in at least a part of a set of current, stale, or deferred indexes in the DBMS. Current indexes are maintained by refreshing a current index synchronously with a table change relating to the current index. Stale indexes are maintained by refreshing a stale index continuously and asynchronously to table modifications of tables relating to the stale index based on log information relating to the modifications. Deferred indexes are maintained by building a deferred index in response to a query to a table relating to the deferred index, thereby bringing the deferred index in accordance with the current query time status to the table relating to the deferred index.
摘要:
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.