公开(公告)号：DE69030228D1

公开(公告)日：1997-04-24

申请号：DE69030228

申请日：1990-10-04

Applicant: IBM

Inventor： DIAS DANIEL MANUEL ,  WOLF JOEL LEONARD ,  SHI-LUNG YU PHILIP

IPC: G06F15/16 ,  G06F9/50 ,  G06F12/00 ,  G06F15/177 ,  G06F17/30 ,  G06F17/40

Abstract: A technique for performing joins in parallel on a multiple processor database system effectively deals with data skew. The join operation is performed in three stages with an optional fourth stage. The first stage is a preparatory stage, the detail of which depends on the underlying join algorithm used. This preparatory stage provides pre-processing the results of which are used in the following stage as the basis for defining subtasks for the final join operation. The data provided in the first stage is used in the second stage to both define subtasks and to optimally allocate these subtasks to different processors in such a manner that the processors are close to equally loaded in the final join operation, even in the presence of data skew. This second stage is an assignment stage the details of which depend on the underlying join algorithm. Once the second stage has completed its processing of the subtasks, the subtasks are shipped to their assigned processors for processing and the final join of the two relations in the third stage. The method used in the final join operation depends on the underlying join algorithm used. Optionally, during the actual join as performed in the third stage, there could be a dynamic re-assignment of the subtasks should the join operation become unbalanced.

公开(公告)号：SG77258A1

公开(公告)日：2000-12-19

申请号：SG1999003465

申请日：1999-07-01

Applicant: IBM

Inventor： MUKHERJEE RAJAT ,  DIAS DANIEL MANUEL

IPC: G06F12/00 ,  G06F9/48 ,  G06F9/50 ,  G06F13/00 ,  G06F15/167 ,  G06F13/18

Abstract: A clustered computer system includes a shared data storage system, preferably a virtual shared disk (VSD) memory system, to which the computers in the cluster write data and from which the computers read data, using data access requests. The data access requests can be associated with deadlines, and individual storage devices in the shared storage system satisfy competing requests based on the deadlines of the requests. The deadlines can be updated and requests can be killed, to facilitate real time data access for, e.g., multimedia applications such as video on demand.

公开(公告)号：CZ9904221A3

公开(公告)日：2000-10-11

申请号：CZ422199

申请日：1998-05-27

Applicant: IBM

Inventor： DIAS DANIEL MANUEL ,  JHINGRAN ANANT DEEP ,  KING RICHARD PERVIN ,  POLYZOIS CHRISTOS

IPC: G06F11/14

公开(公告)号：DE69028373D1

公开(公告)日：1996-10-10

申请号：DE69028373

申请日：1990-10-30

Applicant: IBM

Inventor： DIAS DANIEL MANUEL ,  IYER BALAKRISHNA RAGHAVENDRA ,  YU PHILIP SHI-LUNG

IPC: G06F15/16 ,  G06F15/177 ,  G06F17/30 ,  G06F9/46

Abstract: A multi-processor computer system in which each processor is under the control of separate system software and access a common database. A two level lock management system is used to prevent data corruption due to unsynchronized data access by the multiple processors. By this system, subsets of data in the database are assigned respectively different lock entities. Before a task running on one of the processors access data in the database it first requests permission to access the data in a given mode with reference to the appropriate lock entity. A first level lock manager handles these requests synchronously, using a simplified model of the locking system having shared and exclusive lock modes to either grant or deny the request. All requests are then forwarded to a second level lock manager which grants or denies the requests based on a more robust model of the locking system and queues denied requests. The denied requests are granted, in turn, as the tasks which have been granted access finish processing data in the database.

公开(公告)号：GB2345993B

公开(公告)日：2003-09-17

申请号：GB9919526

申请日：1999-08-19

Applicant: IBM

Inventor： CHALLENGER JAMES ,  DANTZIG PAUL MICHAEL ,  DIAS DANIEL MANUEL ,  IYENGAR ARUN KWANGIL ,  LEVY-ABEGNOLI ERIC

IPC: G06F12/08 ,  G06F12/12 ,  G06F17/30

公开(公告)号：GB2345993A

公开(公告)日：2000-07-26

申请号：GB9919526

申请日：1999-08-19

Applicant: IBM

Inventor： CHALLENGER JAMES ,  DANTZIG PAUL MICHAEL ,  DIAS DANIEL MANUEL ,  IYENGAR ARUN KWANGIL ,  LEVY-ABEGNOLI ERIC

IPC: G06F12/08 ,  G06F12/12 ,  G06F17/30

Abstract: Coordinated, hierarchical caching of objects in a client/server system. In the described embodiment, an encapsulated cluster 70 comprises one or more level 1 nodes 20, e.g. Web server accelerators or routers, each including at least one level 1 cache 30, and one or more level 2 nodes 40, e.g. Web servers, within which the objects are permanently stored or generated on request. Each level 2 node is coupled to at least one level 1 node and includes one or more level 2 caches 50. More levels can be included. Object caching is based on various described criteria: for instance, the level 2 cache(s) can be used to cache dynamic pages which are expensive to create, while the level 1 cache(s) can be used to cache static pages, and hot dynamic pages. Different cache replacement policies for the level 1 cache(s) are also described (Fig. 4), in order to optimize performance whether the performance bottleneck is router processing power, server processing power, or the network between the server(s) and the router.

公开(公告)号：DE69028371D1

公开(公告)日：1996-10-10

申请号：DE69028371

申请日：1990-11-08

Applicant: IBM

Inventor： DIAS DANIEL MANUEL ,  IYER BALAKRISHNA RAGHAVENDRA

IPC: G06F15/173 ,  H04L12/43 ,  H04L12/42

公开(公告)号：DE3751003D1

公开(公告)日：1995-03-02

申请号：DE3751003

申请日：1987-09-18

Applicant: IBM

Inventor： DIAS DANIEL MANUEL ,  LIEN YEONG-CHANG ,  MARUYAMA KIYOSHI

IPC: H04Q3/52 ,  H04L12/56 ,  H04Q11/04 ,  H04L12/54

Abstract: In a method for switching voice and data over a multistage interconnection network (MIN) (10), a plurality of bits are stored in respective storage locations (2-1, 2-2, ... 2-512) of the switching elements (5) of the MIN. Each storage location of a switching element represents a particular time slot in a frame or a sequence of frames. Bits (27, 26) stored in each location represent specific conditions of the inputs and outputs of the switching elements and also indicate which inputs of the switching elements will be connected to which outputs of the switching elements. This storage of control information in the switching elements allows the switching network to rapidly and simultaneously change connections through the switching elements of the network.

公开(公告)号：CA2288016C

公开(公告)日：2004-11-16

申请号：CA2288016

申请日：1998-05-27

Applicant: IBM

Inventor： JHINGRAN ANANT DEEP ,  KING RICHARD PERVIN ,  DIAS DANIEL MANUEL ,  POLYZOIS CHRISTOS

IPC: G06F11/14

Abstract: A method and system for recovering from a failure of a processing node in a partitioned shared nothing database processing system are provided. The processing system may include a pair of processing nodes having twin-tailed-connected thereto a storage device. A first processing node of the pair of processing nodes has a first database instanc e running thereon which accesses a first data partition on the storage device prior to the failure. Upon detection of the failure, access t o the first data partition on the storage device is provided to a third, spare processing node through the second processing node of the pair of processing nodes. The third processing node runs a replacement database instance for the first database instance which was running on the first processing node prior to the failure thereof. The replacement database instance accesses the first data partition on the storage device through the second processing node, thereby recovering from the failure of the first processing node. Access to the first data partition may include using a virtual shared disk utility having a server portion on the second processing node and a client portion on the third processing node.

公开(公告)号：AU2003292269A1

公开(公告)日：2004-06-30

申请号：AU2003292269

申请日：2003-11-14

Applicant: IBM

Inventor： DIAS DANIEL MANUEL ,  LIU ZHEN ,  SQUILLANTE MARK STEVEN ,  XIA HONGHUI ,  YU SHUNG-ZHENG ,  ZHANG LI ,  KING RICHARD PERVIN

IPC: H04L12/24 ,  H04L12/56 ,  H04L29/06 ,  H04L29/08

Abstract: Identifying traffic patterns to web sites based on templates that characterize the arrival of traffic to the web sites is provided. Based on these templates, determinations are made as to which web sites should be co-located so as to optimize resource allocation. Web sites whose templates are complimentary, i.e. a first web site having a peak in arrival traffic at time t1 and a second web site that has a trough in arrival traffic at time t1, are designated as being candidates for co-location. In addition, the templates identified for the traffic patterns of web sites are used to determine thresholds for offloading traffic to other servers. These thresholds include a first threshold at which offloading should be performed, a second threshold that takes into consideration the lead time needed to begin offloading, and a third threshold that takes into consideration a lag time needed to stop offloading of traffic.