When two or more application servers (identity-api) point to the same database, beneficiary registration fails intermittently with a duplicate key constraint violation on the i_beneficiarymapping table.

Error
  java.sql.SQLIntegrityConstraintViolationException: Duplicate entry '37607628' for key 'i_beneficiarymapping.BenRegId_UNIQUE'

Root Cause
The registration ID allocation used an in-memory ArrayDeque queue inside IdentityService. When the queue was empty, each server independently fetched the same top 10,000 unprovisioned/unreserved rows from m_beneficiaryregidmapping into its local queue. Since neither server had committed a reserved=true update at that point, both queues held identical IDs. Concurrent registrations from the two servers then attempted to insert the same BenRegId, causing the constraint violation.

Impact
  - Beneficiary registration fails silently under multi-server deployments
  - Affects all AMRIT applications that register beneficiaries via identity-api
  - Occurs only when two or more servers share the same database instance (Now get in Assam_Prod_Linux)