Associate Data Practitioner · Free Practice Question Medium
Question 6
A financial institution needs to migrate transaction data from an on-premises Oracle database to BigQuery while ensuring minimal downtime. The database is 5TB in size and grows by approximately 50GB per day. Which migration approach would be most appropriate?
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A
Use Datastream for CDC replication during migration
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B
Use Database Migration Service to migrate the Oracle database to Cloud SQL first
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C
Perform a full export and import over a weekend maintenance window
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D
Use BigQuery federation to query the Oracle database directly
Reveal correct answer
Correct answer: A
Explanation
Option A is CORRECT. Datastream provides continuous data replication with Change Data Capture (CDC), enabling a low-downtime migration approach. It can replicate the initial 5TB dataset while capturing ongoing changes, ensuring that BigQuery stays synchronized with the source Oracle database during migration. This approach minimizes disruption to business operations, provides a validation period where both systems can run in parallel, and allows for a smooth cutover with minimal downtime.
Option B is INCORRECT. Migrating to Cloud SQL first introduces an unnecessary intermediate step that increases complexity and extends the migration timeline. This approach requires two migrations instead of one (Oracle → Cloud SQL, then Cloud SQL → BigQuery) and doesn't address the minimal downtime requirement effectively.
Option C is INCORRECT. A full export and import during a weekend maintenance window would be challenging with a 5TB database, as the export, transfer, and import processes would likely exceed a typical weekend maintenance window. This approach also risks data inconsistency for transactions occurring during the migration.
Option D is INCORRECT. BigQuery federation allows querying external databases but doesn't actually migrate the data to BigQuery. This approach would create ongoing performance issues for analytical queries and increase load on the source Oracle system. It's a query solution rather than a migration solution.
Discussion
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