Data Recovery

ENTERPRISE EDITION FEATURE

BendSave is an Enterprise Edition feature. Contact Databend Support for a license.

This topic explains how to back up and restore data in Databend.

Time Travel: Easy Access to Past Data

With Databend Time Travel, you can revisit and retrieve data from the past, even if it's been altered or removed. It's perfect for:

• Getting Back Deleted Data: Helps you get back important things like tables, databases that were deleted, whether by accident or on purpose.

• Copying and Saving Past Data: Lets you copy and save important data from earlier times.

• Looking at Past Data Use: Makes it easier to see how data was used or changed at certain times.

Main Uses of Time Travel

• Access Past Data: Look at data from the past, even if it has been changed or deleted.
• Recover Lost Data: Bring back tables and databases that were deleted using the FLASHBACK TABLE command.

Time Travel SQL Extensions

• SQL Extensions for Time Travel: Use special SQL clauses like AT in SELECT statements and CREATE commands to specify the exact point in history you want to access.
• Revive Deleted Data: Use the UNDROP command for tables, databases.

Setting the Data Retention Period

• Personal Edition: Choose between no retention (0 days) or the default of 1 day.
• Business Edition and Higher:
  • For temporary data: Set to 0 or the default of 1 day.
  • For permanent data: Choose any period from 0 to 90 days.

Note

Setting a retention period of 0 days means Time Travel won't be available for that data.

Adjusting Data Retention Time

Change the data keeping time with the DATA_RETENTION_TIME_IN_DAYS setting, which is usually 1 day. This decides how long to keep old data.

Fail-safe: Extra Protection for Your Data

Fail-safe in Databend Cloud is an additional safety feature, different from Time Travel. It's designed to protect your data in case of system issues or security incidents.

How Fail-safe Works

Fail-safe offers a fixed 7-day recovery window after the Time Travel period ends.

Fail-safe includes:

• MetaData Recovery: Uses versioning in the meta-service to recover deleted tables.
• Data Recovery: Uses AWS S3's versioning to save data that's been changed or deleted.

Attention

• Fail-safe is an emergency service, not user-configurable, provided by Databend Cloud.
• It should be used only after other recovery methods don't work.
• Not intended for regular historical data access beyond the Time Travel period.
• For restoring data after big problems, and you can't set it up yourself.
• Recovery times can vary from a few hours to several days, depending on the situation.

BendSave

BendSave is a command-line tool for backing up and restoring both metadata and actual data files in Databend. It stores backups in S3-compatible object storage, making it ideal for disaster recovery.

Downloading BendSave

The BendSave binary is distributed as part of the Databend release packages.

To download:

1. Go to the latest Databend Releases.

2. Select the release that matches your currently running databend-query version.

3. Download and extract the release package.

4. Inside the extracted archive, locate the bin directory and find the databend-bendsave binary.

Command Reference

To back up the metadata of a Databend cluster:

databend-bendsave backup \
  --from <query-config-path> \
  --to <backup-destination>

Parameter	Description
from	Path to the databend-query.toml configuration file.
to	Backup destination, e.g.,s3://backup?endpoint=http://127.0.0.1:9900&access_key_id=xxx&secret_access_key=xxx. - It is recommended to use environment variables such as AWS_ACCESS_KEY_ID and AWS_SECRET_ACCESS_KEY to provide credentials.

To restore the metadata to a Databend cluster:

databend-bendsave restore \
  --from <backup-source> \
  --to-query <query-config-path> \
  --to-meta <meta-config-path> \
  --confirm

Parameter	Description
from	Backup source path.
to-query	Path to the restored databend-query.toml configuration file.
to-meta	Path to the restored databend-meta.toml configuration file.
confirm	Required flag to confirm restoration and avoid accidental overwrites.

Examples

export AWS_ACCESS_KEY_ID=minioadmin
export AWS_SECRET_ACCESS_KEY=minioadmin

# Backup
./databend-bendsave backup \
  --from ../configs/databend-query.toml \
  --to 's3://backupbucket?endpoint=http://127.0.0.1:9000/&region=us-east-1'

# Restore
./databend-bendsave restore \
  --from "s3://backupbucket?endpoint=http://127.0.0.1:9000/&region=us-east-1" \
  --to-query ../configs/databend-query.toml \
  --to-meta ../configs/databend-meta.toml \
  --confirm

Tutorials

• Backing Up and Restoring Data with BendSave