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Siebel Business Applications use LONG columns on Database Servers to store arbitrarily long character data up to 16350 characters. Examples include scripts, emails, notes, and descriptions. On all RDBMS platforms, except DB2 for z/OS, the size of LONG columns is fixed and is independent of the size of the table space in which the table is defined.
You can estimate the size of the LONGVARCHAR column by calculating the size of the table space minus the size of all non-LONGVARCHAR columns; the LONGVARCHAR column takes up the remainder of the space in the table space. For example, a table containing one LONGVARCHAR column, defined in a 16-KB table space, with a combined byte size for non-LONGVARCHAR columns of 5 KB, results in the LONGVARCHAR column having a size of about 11 KB. For more information on calculating the size of LONGVARCHAR columns, refer to the vendor documentation on the IBM Web site
If Siebel Systems created all LONGVARCHAR columns on DB2 for z/OS with a length of 16350 characters, this would effectively force all tables to a 32-KB table space; this table space size increases buffer pool storage requirements as it requires twice as much storage as a 16-KB table space. To minimize the number of tables created in 32-KB table spaces, during the Siebel installation process, tables with LONGVARCHAR columns are created in a 16-KB table space by default. Siebel Business Applications assume that LONGVARCHAR columns have a logical length of 4046 bytes, which forces the table to be created in a 16-KB table space.
NOTE: Although Siebel Systems sets the LONGVARCHAR column to have a logical length of 4046 bytes, the physical length is not specified in the
By taking this approach, almost all aspects of the Siebel application function without problems. However, if your implementation involves a usage scenario in which very large notes, descriptions, emails, or other items up to 16350 in length are stored, then you need to resolve this by considering one of the following choices:
|Implementing Siebel Business Applications on DB2 UDB for z/OS|