Recovering a Data Sync Issue in Oracle GoldenGate

Recently, I faced a synchronization issue in one of our Oracle GoldenGate (OGG) environments. The setup was designed to extract table data from an Oracle database and replicate it into a Microsoft SQL Server target.

After creating a new extract group using the begin now option, I noticed that a portion of the data had not synced correctly. Recovery was required to ensure the target database was fully consistent.

Here’s the step-by-step process I followed to resolve the issue 👇

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🧰 Step 1: Stop Existing Processes

I began by stopping the currently running extract and replicat groups to prevent any further replication while investigating the issue.

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⚙️ Step 2: Create a New Extract Group

A new extract group was created on the source Oracle database, specifying a precise timestamp to capture all transactions from the point where data loss began.

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📝 Step 3: Update the Parameter File

The new extract group’s parameter file was updated with the required environment settings, database credentials, remote host details, and trail configuration.

Example parameters:

• Environment variables for database and Oracle home

• Replication user credentials

• Remote host and port details

• Trail file path for data capture

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🔗 Step 4: Register and Start the New Extract

The new extract was then registered with the source database to establish proper log reading and transaction capture. Once registered, I started the new extract process.

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🔍 Step 5: Verify and Monitor

I reviewed the extract’s detailed report to confirm that it was running successfully and capturing data from the correct log sequence number.

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✅ Step 6: Confirm Data Recovery

Finally, I validated that the missing data was successfully extracted and replicated to the target MSSQL database, ensuring full synchronization.

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💡 Key Takeaway

When creating a new extract group, avoid using begin now blindly. Always verify the correct start timestamp to prevent missing transactions, especially after an unexpected extract failure. Proper timing and validation ensure smooth and reliable data replication.