EUID Generator

The EUID generator controls how EUIDs are created for each unique record in the master index database. For the default EUID generator, you can define three parameters.

IdLength

This parameter defines the length of the EUIDs created by the master index application. By default, the length of the EUID columns in the master index database is 20. If you choose an ID length larger than 20, make sure to manually modify the length of the EUID columns in the database creation scripts.

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.

ChunkSize

For efficiency, the default EUID generator does not need to query the sbyn_seq_table table in the database each time a new EUID is created. Instead, you can specify a number of EUIDs to be allocated in chunks to the EUID generator. For example, if you specify a chunk size of 1000, EUIDs are allocated to the generator 1000 ID numbers at a time. The generator can process up to 1000 new records and assign all 1000 numbers without needing to query sbyn_seq_table. When all 1000 EUIDs are used, another 1000 are allocated. If the server running the master index application is reset before all 1000 numbers are used, the unused numbers are discarded and never used, meaning that EUIDs might not always be assigned sequentially.

Specifying a chunk size affects the numbering of the EUID column in the sbyn_seq_table. If you specify a chunk size of 1, then each time a new EUID is assigned, the value of the EUID column increases by one. If you specify a larger chunk size, then the value of the EUID column increases by the value of the chunk size each time the allocated EUIDs are used. For example, if you specify a chunk size of 1000, the beginning EUID sequence number is 1000, even though EUIDs are assigned beginning with 0001, then 0002, and so on. When the first 1000 EUIDs are assigned, another 1000 EUID numbers are allocated to the generator and the EUID column changes from 1000 to 2000.