Browse Prior Art Database

Sharing Application Control Data in the Parallel Database Manager

IP.com Disclosure Number: IPCOM000112209D
Original Publication Date: 1994-Apr-01
Included in the Prior Art Database: 2005-Mar-27
Document File: 2 page(s) / 105K

Publishing Venue

IBM

Related People

Chang, DY: AUTHOR [+3]

Abstract

Disclosed is a method to have multiple agent processes to concurrently process the same database application request in a non-reentrant parallel database kernel in the same server node.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 52% of the total text.

Sharing Application Control Data in the Parallel Database Manager

      Disclosed is a method to have multiple agent processes to
concurrently process the same database application request in a
non-reentrant parallel database kernel in the same server node.

      A parallel database manager can be composed of many computers.
The only limit to the number of computers is the hardware
configuration such as the maximum number of the communication
channels.

      The parallel database process model is a message driven
architecture.  There are two message queues in the parallel database
process model: the Database Manager(DBM) queue and the Parallel

Database (PDB) queue.  The DBM queue allows the application processes
to drop the database application requests to the parallel database
server.  The PDB queue receives the internal parallel database
requests from the other parallel database server computers.  A single
pool of SQL agent processes serves both the DBM queue and the PDB
queue.  The agent process which serves the database application
requests is called a coordinate agent process.  The agent process
which serves the parallel database requests is call a subordinate
agent process.  The parallel database server computer which contains
the coordinate agent process of the database application is called
the coordinate node to the database application.  The database server
computers which contain the subordinate agent processes of the
database application are called the subordinate nodes to the database
application.  The Fast Communication Manager(FCM) process is a
special process to send or receive messages between parallel database
server computers.

      The application processes drop database application requests
such as Start/Stop Using Database, Create/Drop Database, and Execute
Database Operation in the DBM queue.  These requests are picked up by
a coordinate agent process.  The coordinate agent process will ask
the FCM process to send the internal parallel database requests to
the other parallel database servers based on the database access
plan.  A database access plan is a database application execution
strategy which is created by the database compiler.  The internal
parallel database requests are dropped into the PDB queue by the FCM
process.  The internal database request will be processed by a
subordinate agent process.  The results of the parallel database
request is sent back to the coordinate node through the FCM processes
on the subordinate node and the coordinate node.

      The major data structures in the Parallel Database Process
Model are Application Control Block(ACB), Application State Anchor
Block (ASAB), and Kernel Control Block(KRCB).  Each database
application process has an ACB in the system shared memory when it
calls the...