Fix idle-in-transaction state by adding explicit transaction boundaries

[Copilot]

Problem

Database connections entering idle in transaction state for query filtering by workflow_instance_id. Connections held open during long-running operations (HTTP calls, biometric processing) occurring after data fetch, blocking VACUUM and exhausting connection pool.

Root Cause

SyncRegistrationServiceImpl read methods lack explicit transaction boundaries. Spring Data JPA opens implicit transactions that remain open through method return, keeping connections active while calling code executes business logic.

Example flow:

// Connection opens transaction here
SyncRegistrationEntity entity = service.findByWorkflowInstanceId(id);
// Transaction still open, connection idle
packetManagerService.getBiometrics(...);  // 2s
authService.authenticate(...);             // 3s  
// Transaction finally closes

Changes

Added transaction annotations to read methods

@Override
@Transactional(readOnly = true)
public SyncRegistrationEntity findByWorkflowInstanceId(String workflowInstanceId) {
    return syncRegistrationDao.findByWorkflowInstanceId(workflowInstanceId);
}

Modified methods (5 total in SyncRegistrationServiceImpl):

• findByWorkflowInstanceId()
• findByRegistrationId()
• findByRegistrationIdAndAdditionalInfoReqId()
• findByPacketId()
• findByAdditionalInfoReqId()

Added monitoring tools

• monitoring/idle_in_transaction_monitor.sql - PostgreSQL queries to track idle connections
• Documentation covering verification and deployment

Impact

• Transactions commit immediately after data fetch
• Connections released before business logic execution
• Read-only flag enables database optimizations
• Zero behavioral changes (backwards compatible)

Verification:

SELECT count(*) FROM pg_stat_activity 
WHERE state = 'idle in transaction' AND datname = 'mosip_regprc';
-- Expected: 0 (previously: multiple)

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