kolusu Site Admin

Joined: 26 Nov 2002 Posts: 12378 Topics: 75 Location: San Jose
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Posted: Thu Jun 22, 2006 10:41 am Post subject: |
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nadh,
DB2 has five private address spaces
1.System Services Address Space (DSN1MSTR): This address space handles system functions such as logging and archiving. This address space is small compared to the database services address space. The default Virtual storage is 2 - 5 MB Depending on your environment.
2.Database Services Address Space (DSN1DBM1): This is the largest DB2 address space. It processes database access requests from local users. IRLM Address Space (IRLMPROC): With no CROSS MEMORY specified,(PC=NO), the control block structure is placed in the Extended Common Service Area (ECSA). This is limited by the amount specified in the MAXIMUM ECSA parameter. With PC=YES, the control blocks are placed in the IRLM address space. Each lock takes 250 bytes of storage and can be used to estimate storage for the control block structure.
3.Distributed Data Facility Address Space (DSN1DIST): This address space supports VTAM communications with other DB2 subsystems and executes database access requests on behalf of remote users. The size of this address space is negligible when compared to the size of the database services address space.
4.Stored Procedures Address Spaces (DSN1SPAS): These are DB2 established address spaces that provide isolated environments in which to execute stored procedures. In DB2 V4 you can have only one stored procedure address space managed by DB2. In DB2 V5 and higher you can have multiple stored procedure address spaces managed by OS/390 workload manager (WLM).
5.Allied Agent Address Spaces: The allied agent address spaces are sometimes referred to as the user address spaces. They include TSO, IMS, CICS, and batch address spaces. In TSO, the DSN command requires 130 KB, and in the rest, the attach code requires approximately 36 KB of virtual storage. In all cases, the attach code must run below 16 MB of virtual storage.
Hope this helps...
Cheers
Kolusu _________________ Kolusu
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