Understanding Sun Master Index Configuration Options

ChecksumLength

The ChecksumLength parameter allows you to specify the length of a checksum value. Checksum values help validate EUIDs to ensure accurate identification of records as they are transmitted throughout the system. The checksum process attaches a number, generated through an algorithm, to the end of a new EUID. When a host system receives this number, it strips off the checksum digits to obtain the EUID, and then recalculates the checksum using the same algorithm process. If the checksum values agree, the host system knows the EUID number is correct. Specify “0” (zero) if you do not want to use the checksum function.

Using a checksum value affects the IdLength parameter. If you specify a checksum length greater than 0, the EUID generator creates sequential EUIDs based on the sbyn_seq_table table, and then appends the checksum value to the end of the EUID to determine the final EUID number. For example, if you set IdLength to 8 and CheckSum to 2, then the EUIDs assigned by the master index application will be 10 characters long. If the next sequence number is 10908000, the EUID assigned to the next record is 10908000 plus the checksum (it might be 1090800034, for example). The next EUID would be 10908001 plus the checksum (1090800125, for example). The first eight digits are sequential, but the last two digits are seemingly arbitrary.

If you use a checksum value, make sure to take into consideration the total length of the EUIDs (IdLength plus ChecksumLength) when determining the length of the EUID columns in the database.