公开(公告)号：CA2422176A1

公开(公告)日：2004-09-14

申请号：CA2422176

申请日：2003-03-14

Applicant: IBM CANADA

Inventor： HURAS MATTHEW A ,  MCINNIS DALE M ,  WINER MICHAEL J ,  MCARTHUR CATHERINE S ,  GOSS JEFFREY J ,  ZHENG ROGER L Q ,  ROMANUFA KERILEY K

IPC: G06F16/11 ,  G06F17/30 ,  G06F17/40

Abstract: A method and system for suspending log-based updating of a database in a manner that permits its resumption without restore, to permit efficient alternation between a log-based update mode and a database access mode. Unplayed log records are protected, as re versions of database pages at a time when the log-based update was suspended. This permits log-based updating to resume where it left off. In order to ensure consistent data for access, a roll-back procedure creates consistent data pagers that are used for access, and discarded when log-based update resumes.

公开(公告)号：CA2422161A1

公开(公告)日：2004-09-14

申请号：CA2422161

申请日：2003-03-14

Applicant: IBM CANADA

Inventor： ROMANUFA KERILEY K ,  HURAS MATTHEW A ,  WINER MICHAEL J ,  FLASZA MIROSLAW A ,  BERKS ROBERT T ,  LAU LEO TAT MAN ,  SACHEDINA AAMER

IPC: G06F7/00 ,  G06F17/30

Abstract: The use of a centralized version table allows for efficient object switching. Rather than synchronizing all database agents to recognize a newly created file as containing the most recent version of a given object, database agents requiring access to the given object need only consult the centralized version table to learn file identity information. That is, the database agents consult the centralized version table to determine which of the files associated with a given object contain the most recent version of the given object. Mechanisms associated with the use of the centralized version table also provide for efficient recovery from a failure that has occurred during an object switching transaction.

公开(公告)号：CA2419883A1

公开(公告)日：2004-08-26

申请号：CA2419883

申请日：2003-02-26

Applicant: IBM CANADA

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

IPC: G06F17/30

Abstract: A system and method for selectively processing log files for enhancing performance of table space recovery by processing only those log files required, as well as choosing which log file to process during recovery for both redo and rollback phases of recover y. The system and method skips the processing of log files that do not contain records of interest for the table space being recovered and determines whether a log file contains anything that nee ds to be played, in particular for the recovery of a subsystem in the database, such as a table space. Pre processing of the log files is not done, rather including tablespace ID correlated with log file ID information is collected while the log files are created. The cross-correlated informati on is used during tablespace recovery to selectively determine which of the log files to process. Some log files may be skipped in cases where not all of the database system is being recovered. A sub set of the database can be recovered, such as a tablespace, and which log files to process is determined based on lock intent.

公开(公告)号：CA2383713A1

公开(公告)日：2003-10-26

申请号：CA2383713

申请日：2002-04-26

Applicant: IBM CANADA

Inventor： HURAS MATTHEW A ,  TREMAINE DAVID ,  BERKS ROBERT T ,  FLASZA MIROSLAW A ,  VALENTIN GARY ,  LAU LEO T M ,  MCARTHUR CATHERINE S ,  WINER MICHAEL J

IPC: G06F16/901 ,  G06F17/30 ,  G06F17/60

Abstract: The invention herein provides method and apparatus for managing attribute- tagged index entries contained in an index by assigning or tagging an index entry attribu te indicator to a newly inserted index entry (that is, at the time when a key data value is inserted into the index, the key data value becomes a newly inserted index entry and an attribute indicator i s tagged to the newly inserted index entry). The index entry can be placed anywhere within the index. Once a group of attribute-tagged index entries have been inserted into the index, the attribute identifiers can be switched off instantaneously (that is, the attribute associated with the attribute indicators is disabled). For example, an attribute identifier can be used to defer accessibility of appropriately attribute-tagged index entries until a predetermined time later when the attribute can be disabled and thus allow users to access the attribute-tagged index entries without having to remove the attribute indicators from the index).

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.