The allocation of reference numbers is controlled by the master database. Each extract may be allocated reference blocks from the master. Elements created in the extract will be allocated reference numbers from the local reference block(s). If no reference block is allocated manually, the system will allocate reference blocks as required. For a Global project, this may require daemon activity.

To avoid this, we recommend that the user should assign a block of reference numbers to the extract when its created, using the REFBLOCK n option. The block of reference numbers will then be available locally. n should reflect the number of users writing to the extract, for example, if you expect to have five users writing to the extract, set n to 5.