How Siebel Tables with LONG Columns Are Stored

On the z/OS platform, LONG columns can be up to 16 KB in length. If Siebel CRM created all LONG columns on DB2 for z/OS with a length of 16,350 characters, this would effectively force all tables to a 32-KB table space, thereby increasing buffer pool storage requirements (each table space is assigned a buffer pool of the same size).

To minimize the number of tables created in 32-KB table spaces, during the Siebel installation process, tables with LONG columns are created in an 8-KB table space by default. In Siebel CRM, LONG columns have an assumed minimum logical length of 4096 bytes, which forces the table to be created in an 8-KB table space. However, some of the larger tables with LONG columns are created in 16-KB table spaces. In addition, the S_SERVICE_SCRPT table is defined in a 32-KB table space because the LONG column in this table needs as much space as possible.

Note: Although Siebel CRM sets the LONG column to have a logical length of 4046 bytes, the physical length is not specified in the CREATE TABLE statements for the LONG column. So the resulting length of a LONG column is still set by DB2 for z/OS to a VARCHAR of the maximum length possible, that is, all the space not used by other columns.