Slot ranges and distributed records

Slot numbers are used to provide a unique identifier for RealTime database (RTDB) records. They are important to take note of while creating records.

Slot ranges establish the ranges of slot numbers that each system uses for record creation. This record separation is needed for collision avoidance during new record creation. You can edit slot numbers in the doas_slotrange Table Edit dialog box shown below.

In a distributed installation, if two systems wish to create records, these new records must be unique to all of the systems within the project. If two systems try to create a new RealTime database (RTDB) record at the same time in the same distributed RTDB table, both systems automatically assign the new record to the next available slot in the table.

A collision occurs as soon as RealTime replication attempts to deliver the new records to the same location. Slot ranges assigned to each system for each RTDB table help prevent such collisions. Slot ranges ensure that, when a system creates a new record, it goes to a unique slot in the specified table (within the range assigned to the system). In other words, slot ranges are used to prevent two systems from creating a new record in the same slot.

Slot range configuration should be performed once at the beginning of the system configuration, and should allow for future expansion. Any change to this configuration involves a re-creation and distribution of the RTDB to all systems.