公开(公告)号：CA2369621A1

公开(公告)日：2003-07-25

申请号：CA2369621

申请日：2002-01-25

Applicant: IBM CANADA

Inventor： POSNER SARAH ,  FLASZA MIROSLAW A ,  WINER MICHAEL J ,  ZHENG ROGER L Q ,  HURAS MATTHEW A ,  GOSS JEFFREY J ,  MEADOWCROFT LORYSA M ,  MCARTHUR CATHERINE S

IPC: G06F9/46 ,  G06F12/00 ,  G06F12/14 ,  G06F13/14 ,  G06F17/30

Abstract: The present invention is directed at a method and apparatus for handling resource transaction requests. By marking a waiting transaction request, having an access mode which is incompatible with the access mode of at least one of the executing transactions, with an ignore bit, a subsequent transaction request with an access mode compatible with the access mode(s) of the executing transaction(s) may receive access to the resource. The subsequent transaction request is then marked with a bypass indicator such that when the executing transactions are finished accessing the resource, the waiting transaction request may be notified it may have access to the resource. By including the ignore bit, each subsequent transaction request which arrives after ignore bit has been set, does not suffer from starvation.

公开(公告)号：CA2322613A1

公开(公告)日：2002-04-06

申请号：CA2322613

申请日：2000-10-06

Applicant: IBM CANADA

Inventor： LYLE ROBERT W ,  WINER MICHAEL J ,  SACHEDINA AAMER ,  HURAS MATTHEW A

IPC: G06F9/46 ,  G06F9/50

Abstract: A stealable latch mechanism for programming environments supporting concurre nt tasks. The latch mechanism has a function for providing a latch to a requesting task, a function for a task holding a latch to release the held latch, a function for a task holding a latch to ma rk the held latch stealable, and a function for a task holding a latch marked stealable to mark the latch unstealable where the held latch is not marked stolen by another task. The function for providing a latch to a requesting task provides that the requesting task will receive on request a latch marke d stealable and held by a holding task. Any resources associated with the stealable latch are placed in a consistent state prior to the requesting task accessing the resources.

公开(公告)号：CA2249080C

公开(公告)日：2001-12-04

申请号：CA2249080

申请日：1998-09-25

Applicant: IBM CANADA

Inventor： ROMANUFA KERILEY K ,  HURAS MATTHEW A ,  WINER MICHAEL J ,  GOSS JEFFREY J ,  HOP HING NELSON ,  LINDSAY BRUCE G

IPC: G06F17/30

Abstract: A method for efficiently searching free space in a relational database management system. The method limits the search to a finite number of space map pages in the free space map. If the configured number of space map pages in the free space map are searched and a page with free space is not found for the row, the row is inserted on the last page, or if no space is available on the last page a new page is created and the row is inserted on the new page. New rows are then appended until some predefined amount of space is filled before a search is done again. As a result, insertion of a row into the database management system does not incur the worst-case cost of searching the entire free space map.

公开(公告)号：CA2306968A1

公开(公告)日：2001-10-28

申请号：CA2306968

申请日：2000-04-28

Applicant: IBM CANADA

Inventor： MCARTHUR CATHERINE ,  WINER MICHAEL J ,  LINDSAY BRUCE G

IPC: G06F17/30

Abstract: A callback to a data manager is earned out from an index manager in a query processing system for an index-data fetch to enable an index page held stabilized by an index manager to remain stabilized during predicate checking or data consumption operations. The ind ex manager locates a data identifier in an index and calls back to a data manager to access the data indicated by the data identifier. The data manager may carry out a predicate check or a data consuming operation on the data and if this is the case the index manager may access the next da ta identifier in the index when the data manager callback is complete. The index page need not be destabilized in such a case.

公开(公告)号：CA2279051A1

公开(公告)日：2001-01-29

申请号：CA2279051

申请日：1999-07-29

Applicant: IBM CANADA

Inventor： WONG CATHARINA K ,  WINER MICHAEL J ,  ZHENG ROGER LUO Q ,  MCKNIGHT KATHY A

IPC: G06F17/30 ,  G06F17/60

Abstract: A lock control data structure for an unit of work of an application program. The unit of work has a set of threads of access for opening a set of objects accessible to th e application program. The lock control data structure has a set of object-specific lock models corresponding to the set of objects, and a lock controller for locking each object in the set of objects . Information regarding the lock requirements for each object are stored in the corresponding object- specific lock model. The lock controller locks and unlocks each object in the set of objects based on the information stored in the corresponding object-specific lock model.

公开(公告)号：CA2279028A1

公开(公告)日：2001-01-29

申请号：CA2279028

申请日：1999-07-29

Applicant: IBM CANADA

Inventor： ZHENG ROGER LUO Q ,  WINER MICHAEL J ,  MCINNIS DALE M ,  HURAS MATTHEW A ,  OFER EFFI

IPC: G06F17/00 ,  G06F17/30

Abstract: A database management system having a dropped table recovery flag. If the dropped table recovery flag is on, at the time that a table is dropped an entry will be made in a dropped table history file. The dropped table history file contains a timestamp of the time of table dro p, a unique dropped table identifier, and table definition information. The system includes a command to permit the table space of a dropped table to be restored and rolled forward to the point of t he dropped table drop. The restored and rolled forward dropped table data is written to a flat file. Th e flat file data is loaded into a recreated table in the current table space to recover the dropped table.