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Difficulty: MediumDesigning Migration Plans and Data Transfer Strategies

An enterprise architecture team is designing a database migration strategy to move an active, mission-critical PostgreSQL database from an on-premises data center to Cloud SQL for PostgreSQL with minimal downtime. Arrange the operational steps in the correct execution sequence from first to last.

  1. 1Establish Cloud Interconnect and provision the empty schema structure on the target Cloud SQL instance.
  2. 2Execute an initial full snapshot migration of existing historical data to the target database instance.
  3. 3Configure continuous Change Data Capture (CDC) replication to stream ongoing transactional changes to the target database.
  4. 4Quiesce write traffic on the source database, verify replication lag reaches zero, and re-point application connection strings to Cloud SQL.

Answer

The correct sequence for a minimal-downtime database migration starts with network and target schema provisioning, followed by the initial bulk historical data load, enabling continuous Change Data Capture (CDC) replication, and concluding with a cutover window where source writes are paused, zero lag is verified, and traffic is re-routed.
A standard minimal-downtime database migration follows a structured lifecycle: establishing connectivity and target schema infrastructure first, carrying out an initial bulk snapshot export/import, initiating continuous CDC stream replication to catch up and maintain sync, and finally performing cutover by stopping source writes, draining replication queues to zero lag, and re-pointing application endpoints.

Step-by-Step Solution

1
Provision network connectivity and target database structure
Cloud Interconnect connects environments and Cloud SQL is initialized with the required schema.
Data transfer targets must be securely accessible and schema-ready before ingesting data.
2
Perform initial bulk baseline data load
Existing bulk records are transferred to establish a baseline snapshot in the target database.
CDC stream synchronization requires a base state snapshot to apply transaction deltas against.
3
Initiate continuous transaction log replication (CDC)
Live changes made to the source database stream continuously to the target database.
Continuous sync minimizes data lag during ongoing production operations prior to cutover.
4
Execute final cutover during maintenance window
Source writes are stopped, remaining replication log items apply, and applications connect to Cloud SQL.
Ensures zero data loss and data consistency across application clients during final cutover.

Key Concept

Minimal-Downtime Database Migration Pipeline Staging
Estimated Time:2m 0s
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Topics

Designing Migration Plans and Data Transfer Strategies