Error handling and retries in DynamoDB

Introduction

Error handling and retries help your program keep working even when something goes wrong with the database. It makes your app more reliable and user-friendly.

When your app tries to save data but the network is slow or unstable.

When you read data but the database temporarily refuses the request.

When you update records but there is a conflict or timeout.

When you want to avoid losing data due to temporary errors.

When you want to give your app a chance to fix small problems automatically.

Syntax

DynamoDB

try {
  // Your DynamoDB operation here
} catch (error) {
  if (shouldRetry(error)) {
    // Retry the operation
  } else {
    // Handle the error (log, alert, etc.)
  }
}

function shouldRetry(error) {
  // Check error type or code to decide if retry is needed
  return error.name === 'ProvisionedThroughputExceededException';
}

Use try-catch blocks to catch errors from DynamoDB operations.

Decide to retry only for temporary errors like throttling or timeouts.

Examples

This example retries only when DynamoDB says you sent too many requests.

DynamoDB

try {
  const result = await dynamoDbClient.get(params).promise();
  console.log('Data:', result.Item);
} catch (error) {
  if (error.name === 'ProvisionedThroughputExceededException') {
    console.log('Too many requests, retrying...');
    // retry logic here
  } else {
    console.error('Error:', error.message);
  }
}

This example handles throttling errors during data saving.

DynamoDB

try {
  await dynamoDbClient.put(params).promise();
  console.log('Data saved');
} catch (error) {
  if (error.name === 'ProvisionedThroughputExceededException') {
    console.log('Request throttled, retrying...');
    // retry logic here
  } else {
    console.error('Failed to save data:', error.message);
  }
}

This example does not retry for unknown errors to avoid infinite loops.

DynamoDB

try {
  const result = await dynamoDbClient.update(params).promise();
  console.log('Update successful');
} catch (error) {
  console.error('Update failed:', error.message);
  // No retry for unknown errors
}

Sample Program

This program tries to get an item from DynamoDB. If it gets a throttling error, it waits and retries up to 3 times. It prints messages to show what is happening.

DynamoDB

import { DynamoDBClient, GetItemCommand } from '@aws-sdk/client-dynamodb';

const dynamoDbClient = new DynamoDBClient({ region: 'us-east-1' });

async function getItemWithRetry(params, maxRetries = 3) {
  let attempt = 0;
  while (attempt < maxRetries) {
    try {
      const command = new GetItemCommand(params);
      const result = await dynamoDbClient.send(command);
      return result.Item;
    } catch (error) {
      if (error.name === 'ProvisionedThroughputExceededException') {
        attempt++;
        console.log(`Attempt ${attempt} failed due to throttling. Retrying...`);
        await new Promise(resolve => setTimeout(resolve, 1000 * attempt));
      } else {
        console.error('Non-retryable error:', error.message);
        throw error;
      }
    }
  }
  throw new Error('Max retries reached. Could not get item.');
}

(async () => {
  const params = {
    TableName: 'MyTable',
    Key: {
      'Id': { S: '123' }
    }
  };

  try {
    console.log('Trying to get item...');
    const item = await getItemWithRetry(params);
    console.log('Item received:', item);
  } catch (error) {
    console.error('Failed to get item:', error.message);
  }
})();

Important Notes

Retrying helps handle temporary errors but too many retries can slow your app.

Use exponential backoff (waiting longer between retries) to be polite to the database.

Always limit retries to avoid infinite loops.

Summary

Error handling keeps your app stable when problems happen.

Retries let your app try again after temporary errors like throttling.

Use try-catch and check error codes to decide when to retry.