System Wide Catalog

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In V3R1, a new feature in DB2/400, the System Wide Catalog, contains information for each physical file, logical file, SQL table, and SQL view stored on a given AS/400. The System Wide Catalog provides one central place on an AS/400 for the attributes and characteristics of all the above file types existing on a system.

In V3R1, this new catalog is used to implement and support referential integrity, client/server application development tools, and client/server applications. It can also be used by software/application providers to install their packages and avoid naming convention conflicts with files already on a system.

When V3R1 is installed on a system, this new System Wide Catalog must be created and updated with the information for all files existing on the system. This update task is CPU intensive and will increase the amount of time and disk space required to install V3R1 from about two minutes and an additional 22MB of disk space for 1,500 files to about three hours and an additional 220MB of disk space for 15,000 files. You need to do this only with the installation of V3R1.

Any new file added to a system after V3R1 is installed will cause the catalog update task to be triggered. This is a CPU intensive task that may run at the highest priority on the system (priority number of 10 or less). So if you restore a new or existing library that contains a large number of files not currently existing on the system, or if you rename an existing library that has a large number of files in it, the catalog update task can be triggered. This will have a serious performance impact on the system.

If you must restore libraries with a large number of new files or rename existing libraries, it is wise to do it during off-peak operations.

- Skip Marchesani

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