BigQuery table restoration usecases

Google Cloud Data Analytics
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Apologies for the confusion earlier. Let’s clarify the approach for data recovery in BigQuery, especially for periods beyond the 7-day Time Travel window:

1. Retrieving Data Beyond the 7-Day Time Travel Window:

BigQuery’s built-in Time Travel feature is convenient but is limited to a 7-day window. To recover data from older points in time, you’ll need to consider the following strategies:

  • Option 1: Regular Backups/Snapshots:
    • Proactively create regular backups or snapshots of your essential BigQuery tables. Store these backups in Google Cloud Storage for long-term preservation.
    • To restore data from a previous time, you can load from these backups into BigQuery.
    • Refer to the BigQuery documentation for guidance on creating snapshots: https://cloud.google.com/bigquery/docs/table-snapshots-intro
  • Option 2: Data History in Application Logic:
    • If you need to recover very specific data (e.g., revert a few records to a previous state), you could implement data history or an audit log directly within your application’s logic.
    • This approach can offer more granular control over recovery but requires additional development effort.

2. Pricing of Restoration Queries:

  • BigQuery charges for queries based on the amount of data processed. This applies to both standard queries and Time Travel queries.
  • The cost of restoring data will depend on the size of the data being queried at that specific point in time.
  • Remember that storing snapshots/backups will incur storage costs in Google Cloud Storage.
  • For up-to-date pricing information, refer to the BigQuery pricing page: https://cloud.google.com/bigquery/pricing

Example for Restoring Data within the 7-Day Time Travel Window:

To restore a table to its state from yesterday, you would use a Time Travel query like this:

-- Query to go back one day:
SELECT * FROM `project.dataset.table` 
FOR SYSTEM_TIME AS OF TIMESTAMP_SUB(CURRENT_TIMESTAMP(), INTERVAL 1 DAY);

Additional Considerations:

  • Backup Strategy: Carefully decide on a backup strategy that aligns with your business’s data retention and recovery needs. Regular backups are crucial.
  • Testing Recovery Process: Make sure you regularly test your backup and recovery processes to ensure you can recover data successfully when needed.
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