How to Paginate Query & Scan Results with the DynamoDB PHP Client

Posted on by Christopher Davis

This bit of AWS Docs has all the info you could possible need on DynamoDB pagination, but it’s wordy. So here’s a quick summary and code sample for PHP.

  • DynamoDB respects a Limit argument in both Scan and Query, but it will also stop if the retrieved items exceed one megabyte regarldess of Limit.
  • If there are more items a LastEvaluatedKey will be returned in the response.
  • Pass that LastEvaluatedKey to ExclusiveStartKey in the next request.
use Aws\DynamoDb\DynamoDbClient;

function queryAll(DynamoDbClient $dynamo, array $request)
{
    $allItems = [];
    $lastEvaluatedKey = null;
    do {
        // copy so we don't mess with the original request
        $currentRequest = $request;
        $currentRequest['Limit'] = 10; // optional
        if ($lastEvaluatedKey) {
            $currentRequest['ExclusiveStartKey'] = $lastEvaluatedKey;
        }
        

        $response = $dynamo->query($currentRequest);

        // collect the returned items
        $allItems = array_merge($allItems, $response['Items'] ?? []);

        // grab the last evaluated key, and keep querying if it's present
        $lastEvaluatedKey = $response['LastEvaluatedKey'] ?? null;
    } while ($lastEvaluatedKey);
}

queryAll(new DynamoDbClient([
    'version' => 'latest',
    'region' => 'us-east-1',
]), [
    'TableName' => 'YourTable',
    'IndexName' => 'SomeSecondaryIndex',
    'KeyConditionExpression' => 'YourKey = :whatever',
    'ExpressionAttributeValues' => [
        ':whatever' => [
            'S' => 'abc123',
        ],
    ]
]);

This is really close to the seek method in SQL.