Abstract: A method, system, and computer program product to create an access control bit mapping (ACBM) structure for a corresponding database table are disclosed. The ACBM structure may include a relative record number (RRN) bit map. The RRN bit map may describe the access rights for a parameter. The computer-implemented method may maintain one or more statistics describing the RRN bit map. The method may additionally provide for updating the ACBM structure. The method may also provide for using the ACBM structure to process a database query.

Abstract: In an embodiment, a hit percentage of an expected affinity for a first query is calculated, wherein the expected affinity comprises a first address range in a query plan cache, a hit percentage of a candidate affinity for the first query is calculated, wherein the candidate affinity comprises a second address range in a query plan cache, and if the hit percentage of the candidate affinity is greater than the hit percentage of the expected affinity by more than a threshold amount, query plans in the candidate affinity are swapped with query plans in the expected affinity.

Abstract: In an embodiment, a hit percentage of an expected affinity for a first query is calculated, wherein the expected affinity comprises a first address range in a query plan cache, a hit percentage of a candidate affinity for the first query is calculated, wherein the candidate affinity comprises a second address range in a query plan cache, and if the hit percentage of the candidate affinity is greater than the hit percentage of the expected affinity by more than a threshold amount, query plans in the candidate affinity are swapped with query plans in the expected affinity.

Abstract: In an embodiment, a first query is received that specifies a first object identifier. If a first query plan exists that implements the first query, except that the first query plan does not comprise the first object identifier and instead comprises a parameter marker in place of the first object identifier, a first query execution plan is created from the first query plan, substituting the first object identifier in the first query execution plan for the parameter marker, and the first query execution plan is executed to read a first object identified by the first object identifier.

Abstract: In an embodiment, a query implemented by a first execution plan is executed at a first virtual machine. In response to a move command that requests a move of the first virtual machine from a first computer to a second computer while the first virtual machine is executing the query implemented by the first execution plan at the first computer, an attribute of a resource used by the executing at the first virtual machine is saved to memory at the first computer and a driver source used by the executing at the first virtual machine is saved to the memory at the first computer. In response to a command that requests starting a second virtual machine at the second computer, a determination is made whether the driver source that comprises the state of the partial execution of the first execution plan exists in memory of the second computer.

Abstract: In an embodiment, a query plan is compressed to data in a cache at a high compression level if a runtime of a query that the query plan implements is greater than a high time threshold. The query plan is compressed to the data in the cache at a medium compression level if the runtime of the query that the query plan implements is less than the high time threshold and greater than a low time threshold. The query plan is stored to the data in the cache at an uncompressed level if the runtime of the query that the query plan implements is less than the low time threshold.

Abstract: In an embodiment, a plurality of estimates of costs of executing a plurality of respective queries is received from a plurality of respective virtual machines using a plurality of respective estimated resources allocated to the plurality of respective virtual machines. A selected virtual machine of the plurality of respective virtual machines is selected with a lowest weighted cost ratio, as compared to all other of the plurality of respective virtual machines. A source virtual machine is found with a lowest current resource usage. An amount of a resource to deallocate from the source virtual machine is calculated, which further comprises estimating the amount of the resource to deallocate that does not raise the lowest current resource usage over a maximum resource threshold. The amount of the resource from the source virtual machine is deallocated. The amount of the resource is allocated to the selected virtual machine.

Abstract: Techniques are disclosed for identifying impact of a patch. One embodiment of the invention provides a DBMS that is configured to manage one or more databases. The DBMS may receive a request to evaluate a patch for the DBMS. The DBMS provides a first execution environment that is not based on the patch and a second execution environment that is based on the patch. For each query, the DBMS compares a first access plan with a second access plan, where the first access plan is generated from the first execution environment and the second access plan is generated from the second execution environment. The DBMS identifies one or more queries having differing access plans, based on the comparisons.

Abstract: In an embodiment, a query implemented by a first execution plan is executed at a first virtual machine. In response to a move command that requests a move of the first virtual machine from a first computer to a second computer while the first virtual machine is executing the query implemented by the first execution plan at the first computer, an attribute of a resource used by the executing at the first virtual machine is saved to memory at the first computer and a driver source used by the executing at the first virtual machine is saved to the memory at the first computer. In response to a command that requests starting a second virtual machine at the second computer, a determination is made whether the driver source that comprises the state of the partial execution of the first execution plan exists in memory of the second computer.

Abstract: A method, computer-readable storage medium, and computer system are provided. In an embodiment, in response to receiving a first command that specifies first data, a first cryptographic key, and a column identifier that identifies a column of rows in a database, the first data is encrypted into encrypted data using the first cryptographic key. The encrypted data is stored to a first row in the column in the database. In response to the receiving the first command, characterization data is created that specifies valid contents of the column of the rows. In response to receiving a query command that specifies a second cryptographic key and the column, the column is decrypted using the second key to create decrypted data. If the decrypted data does not satisfy the valid contents specified by the characterization data, an invalid cryptographic key action is performed.

Abstract: In an embodiment, a threshold value is calculated for a current entry in a first column of an index. If the current entry has been read a number of times by execution of an execution plan that is more than the threshold value and the current entry points to at least one row in a table and not all of the at least one row have been selected by the execution plan for inclusion in a result set as satisfying a query that the execution plan implements, then a new entry is added to the index.

Abstract: A method, apparatus and program product that determine a density of a key value referenced in a database query over at least one range of rows, and utilize the determined density to optimize the database query. By doing so, the density of various key values may be determined and compared, and a bit map may be generated over the range of rows of the key value that is denser, resulting in a reduction of resources to build and use the bit map. Moreover, from the bit map over the range of rows to be selected after using the determined density, dense regions may be identified that can be used to optimize block I/O's according to the number of rows to be selected based on the query.

Abstract: A partially built index is used in a computer database system. When a database index is being built, or rebuilt, the database manager keeps track of the records processed using a relative row number (RRN) to track what part of the partially built index is complete. Queries are optimized by a query optimizer associated with the database manager that uses the portion of the index that is complete with reference to the RRN. The remainder of the database table beyond the RRN can be estimated or implemented using the completed data or can be determined by searching the relevant portion of the database table.

Abstract: Techniques are disclosed for reorganizing rows of a database table. In one embodiment, each row is associated with a respective row identifier. A mapping is provided that assigns a logical identifier to each row identifier. Each database index on the database table is configured to use the logical identifier rather than the row identifier. Accordingly, the rows of the database table may be reorganized without having to modify any database index on the database table.

Abstract: Systems, methods and computer program products are disclosed for managing a database cache. In one embodiment, access to a data object stored in a database is monitored. A memory residency priority for the data object is determined, based on the access patterns. Further, an access plan is determined for a query, based on the memory residency priority. Access to the data object is also monitored when the access plan is executed, thereby providing a feedback loop between determining memory residency priorities and determining query access plans.

Abstract: A partially built index is used in a computer database system. When a database index is being built, or rebuilt, the database manager keeps track of the records processed using a relative row number (RRN) to track what part of the partially built index is complete. Queries are optimized by a query optimizer associated with the database manager that uses the portion of the index that is complete with reference to the RRN. The remainder of the database table beyond the RRN can be estimated or implemented using the completed data or can be determined by searching the relevant portion of the database table.

Abstract: In an embodiment, a threshold value is calculated for a current entry in a first column of an index. If the current entry has been read a number of times by execution of an execution plan that is more than the threshold value and the current entry points to at least one row in a table and not all of the at least one row have been selected by the execution plan for inclusion in a result set as satisfying a query that the execution plan implements, then a new entry is added to the index.

Abstract: A method, apparatus and program product that determine a density of a key value referenced in a database query over at least one range of rows, and utilize the determined density to optimize the database query. By doing so, the density of various key values may be determined and compared, and a bit map may be generated over the range of rows of the key value that is denser, resulting in a reduction of resources to build and use the bit map. Moreover, from the bit map over the range of rows to be selected after using the determined density, dense regions may be identified that can be used to optimize block I/O's according to the number of rows to be selected based on the query.

Abstract: Techniques are disclosed for identifying impact of a patch. One embodiment of the invention provides a DBMS that is configured to manage one or more databases. The DBMS may receive a request to evaluate a patch for the DBMS. The DBMS provides a first execution environment that is not based on the patch and a second execution environment that is based on the patch. For each query, the DBMS compares a first access plan with a second access plan, where the first access plan is generated from the first execution environment and the second access plan is generated from the second execution environment. The DBMS identifies one or more queries having differing access plans, based on the comparisons.

Abstract: Techniques are disclosed for reorganizing rows of a database table. In one embodiment, each row is associated with a respective row identifier. A mapping is provided that assigns a logical identifier to each row identifier. Each database index on the database table is configured to use the logical identifier rather than the row identifier. Accordingly, the rows of the database table may be reorganized without having to modify any database index on the database table.