Point-in-time recovery (PITR) in DynamoDB - Step-by-Step Execution

Concept Flow - Point-in-time recovery (PITR)

Enable PITR on Table

↓

Continuous Backups

↓

Data Changes Recorded

↓

Choose Recovery Time

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Restore Table to Chosen Time

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New Table Created with Restored Data

PITR keeps continuous backups of your DynamoDB table. You pick a time, and it restores the table to that exact moment.

Execution Sample

DynamoDB

1. Enable PITR on 'Orders' table
2. Make changes: add, update, delete items
3. Choose recovery time: 10:00 AM
4. Restore table to 10:00 AM state

Shows enabling PITR, making changes, then restoring the table to a past time.

Execution Table

Step	Action	Backup State	Recovery Time Chosen	Result
1	Enable PITR on 'Orders'	Backups start from now	None	PITR enabled
2	Add item A	Backup records item A	None	Item A added
3	Update item B	Backup records update	None	Item B updated
4	Delete item C	Backup records deletion	None	Item C deleted
5	Choose recovery time 10:00 AM	Backups up to 10:00 AM	10:00 AM	Recovery time set
6	Restore table to 10:00 AM	Backups used to restore	10:00 AM	New table with data as of 10:00 AM created
7	Use restored table	N/A	10:00 AM	Data reflects state at 10:00 AM

💡 Restoration completes with a new table reflecting the chosen point in time.

Variable Tracker

Variable	Start	After Step 2	After Step 3	After Step 4	After Step 6
Table Data	Empty	Item A added	Item B updated	Item C deleted	Restored to 10:00 AM state

Key Moments - 2 Insights

Why does PITR create a new table instead of changing the original?

Because the original table keeps changing, PITR restores data to a new table to avoid overwriting current data, as shown in step 6 of the execution_table.

Can I restore to a time before PITR was enabled?

No, PITR only keeps backups from when it was enabled, so recovery times before enabling are not available, as seen in step 1 where backups start.

Visual Quiz - 3 Questions

Look at the execution_table, what is the backup state after adding item A?

A Backups start from now

B Backup records deletion

C Backup records item A

D Backups up to 10:00 AM

💡 Hint

Check the 'Backup State' column at step 2 in the execution_table.

At which step is the recovery time chosen?

A Step 4

B Step 5

C Step 6

D Step 7

💡 Hint

Look for 'Choose recovery time' action in the execution_table.

If PITR was not enabled, what would happen when trying to restore?

A Restoration would fail because no backups exist

B Restoration would create a new table anyway

C Original table would be overwritten

D Restoration would restore to current time

💡 Hint

Refer to step 1 where backups start only after PITR is enabled.

Concept Snapshot

Point-in-time recovery (PITR) in DynamoDB:
- Enable PITR to start continuous backups
- Changes are recorded automatically
- Choose any time within retention to restore
- Restoration creates a new table with data at that time
- Original table remains unchanged during recovery

Full Transcript

Point-in-time recovery (PITR) in DynamoDB allows you to protect your table data by continuously backing up changes. Once enabled, every change to the table is recorded. When you want to recover, you pick a specific time, and DynamoDB creates a new table that reflects the data as it was at that moment. This way, your original table stays safe and unchanged. PITR only works from the time you enable it, so you cannot restore to times before activation. This process helps you fix mistakes or recover lost data easily.

Practice

1. What is the main purpose of Point-in-time recovery (PITR) in DynamoDB?

easy

A. To automatically delete old data after 35 days

B. To increase the read capacity of a table

C. To create backups only once a day

D. To restore a table to any second within the last 35 days

Solution

1. Step 1: Understand PITR functionality

   PITR allows restoring a DynamoDB table to a specific second in the past 35 days.

2. Step 2: Compare options with PITR purpose

   Options A, B, and D describe unrelated features; only To restore a table to any second within the last 35 days matches PITR's main purpose.

3. Final Answer:

   To restore a table to any second within the last 35 days -> Option D

4. Quick Check:

   PITR = Restore to any second in 35 days [OK]

Hint: PITR = restore table to any second in last 35 days [OK]

Common Mistakes:

• Confusing PITR with daily backups
• Thinking PITR deletes old data
• Assuming PITR changes table capacity

2. Which AWS CLI command enables Point-in-time recovery (PITR) on a DynamoDB table named Orders?

easy

A. aws dynamodb restore-table-to-point-in-time --table-name Orders --enable-pitr

B. aws dynamodb enable-pitr --table Orders

C. aws dynamodb update-continuous-backups --table-name Orders --point-in-time-recovery-specification PointInTimeRecoveryStatus=ENABLED

D. aws dynamodb start-backup --table-name Orders --pitr true

Solution

1. Step 1: Identify correct command to enable PITR

   The command to enable PITR is update-continuous-backups with the flag --point-in-time-recovery-specification PointInTimeRecoveryStatus=ENABLED.

2. Step 2: Check options for syntax correctness

   aws dynamodb update-continuous-backups --table-name Orders --point-in-time-recovery-specification PointInTimeRecoveryStatus=ENABLED matches the correct syntax; others use invalid commands or flags.

3. Final Answer:

   aws dynamodb update-continuous-backups --table-name Orders --point-in-time-recovery-specification PointInTimeRecoveryStatus=ENABLED -> Option C

4. Quick Check:

   Enable PITR = update-continuous-backups with PointInTimeRecoveryStatus=ENABLED [OK]

Hint: Enable PITR with update-continuous-backups and PointInTimeRecoveryStatus=ENABLED [OK]

Common Mistakes:

• Using non-existent commands like enable-pitr
• Confusing backup start with PITR enable
• Trying to enable PITR during restore

3. Given the following AWS CLI command, what will happen?

aws dynamodb restore-table-to-point-in-time --source-table-name Sales --target-table-name SalesBackup --restore-date-time 1714564800

medium

A. A new table named SalesBackup will be created with data from May 1, 2024, 12:00 UTC

B. The Sales table will be overwritten with data from May 1, 2024, 12:00 UTC

C. The Sales table will be backed up without changes

D. The command will fail because restore-date-time is invalid

Solution

1. Step 1: Understand restore-table-to-point-in-time behavior

   This command creates a new table with the restored data; it does not overwrite the source table.

2. Step 2: Analyze command parameters

   The --target-table-name SalesBackup means the restored data goes into a new table named SalesBackup.

3. Final Answer:

   A new table named SalesBackup will be created with data from May 1, 2024, 12:00 UTC -> Option A

4. Quick Check:

   Restore creates new table = SalesBackup [OK]

Hint: Restore always creates new table, original stays safe [OK]

Common Mistakes:

• Thinking restore overwrites original table
• Confusing backup with restore commands
• Assuming restore-date-time format is invalid

4. You run this command to restore a table:

aws dynamodb restore-table-to-point-in-time --source-table-name Inventory --target-table-name Inventory --restore-date-time 1704067200

But it fails with an error. What is the likely cause?

medium

A. The source table does not have PITR enabled

B. The target table name must be different from the source table name

C. The command is missing the restore-date-time parameter

D. The AWS CLI version is outdated

Solution

1. Step 1: Check restore-table-to-point-in-time requirements

   The target table name must be unique and cannot be the same as the source table.

2. Step 2: Analyze the command error cause

   Using the same name for source and target causes a conflict and failure.

3. Final Answer:

   The target table name must be different from the source table name -> Option B

4. Quick Check:

   Target table name ≠ source table name [OK]

Hint: Target table name must differ from source table name [OK]

Common Mistakes:

• Assuming restore overwrites existing table
• Overlooking that PITR must be enabled on the source table
• Blaming AWS CLI version without checking names

5. You enabled PITR on a table Users 10 days ago. Today, you want to restore it to the state exactly 40 days ago. What will happen if you try to restore using PITR?

hard

A. The restore will fail because PITR only supports recovery up to 35 days in the past

B. The table will be restored to the closest available backup at 35 days ago

C. The table will be restored to the current state since 40 days is out of range

D. The restore will succeed and recover data from 40 days ago

Solution

1. Step 1: Recall PITR retention period

   PITR supports restoring data only within the last 35 days from the current time.

2. Step 2: Analyze restore request for 40 days ago

   Requesting restore beyond 35 days is outside PITR limits and will cause failure.

3. Final Answer:

   The restore will fail because PITR only supports recovery up to 35 days in the past -> Option A

4. Quick Check:

   PITR limit = 35 days; 40 days restore fails [OK]

Hint: PITR max restore window is 35 days only [OK]

Common Mistakes:

• Assuming PITR can restore beyond 35 days
• Thinking restore auto-adjusts to closest backup
• Confusing PITR with manual snapshot backups