公开(公告)号：CA2419900A1

公开(公告)日：2004-08-26

申请号：CA2419900

申请日：2003-02-26

Applicant: IBM CANADA

Inventor： SACHEDINA AAMER ,  ROMANUFA KERILEY K

IPC: G06F12/02 ,  G06F17/30

Abstract: A system and method for directing a database management system to reloca te buffer pages that are pinned in a buffer pool in a data processing system. Each of the buffer pages have a respective page descriptor for indicating the location o f the buffer page in the buffer pool. Once the pages are relocated, the now free system memory of the buffer pool is resized. Prior to resizing, a selected pinned page is latched by an agent of the system, wherein the selected page of the buffer pages is in a resize region of the buffer pool. The pinned and latched page thereby becomes a fixed page. The agent for the database management system, such as a determinator module, also determin es a suitable relocation region of the buffer pool for the fixed page, and a resizer module coupled to the determinator module copies the contents of the fixed page to the relocation region and changes the respective page descriptor to indicate the relocation region. The resizer module performs the relocation for other pages in the resize region to allow dynamic resizing of the buffer pool, while maintaining the presence of pinne d versions of the pages in the buffer pool prior to resizing.

公开(公告)号：CA2353017C

公开(公告)日：2004-03-16

申请号：CA2353017

申请日：2001-07-12

Applicant: IBM CANADA

Inventor： SCHLAMB KELLY W ,  ZHENG ROGER L ,  HURAS MATTHEW A ,  LI JOHN ,  ROMANUFA KERILEY K ,  SACHEDINA AAMER

IPC: G06F3/06 ,  G06F11/14 ,  G06F11/20 ,  G06F17/30 ,  G11B27/10 ,  G11B25/04

Abstract: Writes to a disk by a set of application processes in a database management system are managed. The database management system provides data buffering, direct disk access and asynchronous tasks for managing the data buffering. Each application process seeking to write to the disk acquires a disk latch in SHARED mode before writing to the disk and releases the disk latch following completion of the write to the disk. A user process is able to suspend disk writes by issuing a pause command to asynchronous tasks and acquiring the disk latch i n EXCLUSIVE mode. The user process resumes disk writes by issuing a resume command to the asynchronous tasks and releasing the disk latch.

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.