David L Janicek Deceased16385 Fm 1094, Cat Spring, TX 78933

5430871, Jul 4, 1995

Oct 27, 1992

7/970336

Anouar Jamoussi - Houston TX
David L. Janicek - Houston TX

BMC Software, Inc. - Houston TX

G06F 742
G06F 1200

395600

In a novel method of dynamically adding or removing active logs in a DB2 subsystem without the necessity of cycling DB2, a set of control blocks emulating certain DB2 control blocks is constructed. In adding an active log, a call to a DB2 module is made to allocate the new active log data set and create a new LDSD control block for the new active log data set. The NEW and REUSABLE status flags are set in the new LDSD control block, initialization of the new LDSD control block is completed, and the new LDSD control block is added to the LDSD chain off the LMB. The BSDS record(s) and the cached portions of the BSDS information are updated to reflect the addition of the new active log. In removing an active log, the LDSD of the active log is removed from the LDSD chain and an attempt is made to deallocate the active log data set via a call to a DB2 module. If the deallocation attempt is unsuccessful, the active log's LDSD is reinserted in the chain off the LDSD; if the attempt is successful the BSDS and the cached portions of the BSDS are updated to reflect the removal of the active log.

5432933, Jul 11, 1995

Oct 27, 1992

7/970335

David L. Janicek - Stafford TX

BMC Software, Inc. - Houston TX

G06F 946

395650

A DB2 thread cancellation method permits operator intervention to terminate a DB2 thread. After the thread to be canceled has been located, a series of one or more SRBs is scheduled to cancel the thread. The basic approach is an iterative one, involving (1) making the thread nondispatchable, i. e. , freezing execution of work associated with the thread to prevent such work from making undesirable environmental changes while the thread canceling operation is in progress, (2) testing to ensure that canceling the thread at that moment will not create certain undesirable side effects, primarily in the context of serialization of DB2 resource usage; (3) invoking the DB2 thread cancellation routine; (4) making the thread dispatchable again to permit the cancellation process to begin; (5) receiving a message whether the cancellation request was completed successfully, and (6) returning a status code indicating a successful or unsuccessful cancellation attempt. The foregoing steps are repeated until a success status code is received or until a timeout, i. e. , until a specified number of unsuccessful attempts has been made.

5440692, Aug 8, 1995

Oct 27, 1992

7/970337

David L. Janicek - Stafford TX

BMC Software, Inc. - Houston TX

G06F 1200

395700

A method of dynamically expanding or contracting a DB2 buffer pool, a set of control blocks emulating certain DB2 control blocks is constructed. If the size of the buffer pool is to be increased, the buffer pool expansion routine used by DB2 to accommodate abnormally high storage demand is repeatedly invoked to perform the expansion. However, the contractable-page flag that is set by DB2 for each 4K or 32K page that is added to the buffer pool in this way, indicating that the added page should be removed from the buffer pool as soon as the high storage demand condition has ended, is reset. If the size of the buffer pool is to be decreased, pages are removed from DB2's three queues or chains used to manage the buffer pool, i. e. , the never-used chain, the previously-used chain, and the in-use chain, in that order; in the latter two cases the pages are "removed" by marking them as contractable pages so that DB2 itself will soon remove the pages from the appropriate chain as part of its own normal processing.