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Instrumenting your Application with AWS X-Ray Instrumenting your Node.js application The AWS X-Ray SDK for Node.js provides middleware that you can use to instrument incoming HTTP requests. You need to add the SDK to your application’s dependencies, usually via package.json. Initialize the SDK client and add it to your application prior to declaring routes. var AWSXRay = require('aws-xray-sdk'); AWSXRay.setDaemonAddress('host:port'); app.use(AWSXRay.express.openSegment('MyApp'));       3. Lastly, use the SDK exceptions after declaring routes. app.get('/', function (req, res) {   res.render('index'); }); app.use(AWSXRay.express.closeSegment()); Instrumenting your Java application The AWS X-Ray SDK for Java provides a servlet filter that you can add to your [...]

Calculating the Required Read and Write Capacity Unit for your DynamoDB Table Read Capacity Unit On-Demand Mode When you choose on-demand mode, DynamoDB instantly accommodates your workloads as they ramp up or down to any previously reached traffic level. If a workload’s traffic level hits a new peak, DynamoDB adapts rapidly to accommodate the workload. The request rate is only limited by the DynamoDB throughput default table limits, but it can be raised upon request. For on-demand mode tables, you don't need to specify how much read throughput you expect your application to perform. DynamoDB charges you for the reads [...]

AWS Lambda Integration with Amazon DynamoDB Streams Amazon DynamoDB is integrated with AWS Lambda so that you can create triggers, which are pieces of code that automatically respond to events in DynamoDB Streams. With triggers, you can build applications that react to data modifications in DynamoDB tables. After you enable DynamoDB Streams on a table, associate the DynamoDB table with a Lambda function. AWS Lambda polls the stream and invokes your Lambda function synchronously when it detects new stream records.  Configure the StreamSpecification you want for your DynamoDB Streams: StreamEnabled (Boolean) - indicates whether DynamoDB Streams is enabled (true) or [...]

Kinesis Scaling, Resharding and Parallel Processing Kinesis Resharding enables you to increase or decrease the number of shards in a stream in order to adapt to changes in the rate of data flowing through the stream. Resharding is always pairwise. You cannot split into more than two shards in a single operation, and you cannot merge more than two shards in a single operation. The Kinesis Client Library (KCL) tracks the shards in the stream using an Amazon DynamoDB table, and adapts to changes in the number of shards that result from resharding. When new shards are created as a [...]

DynamoDB Scan vs Query Scan The Scan operation returns one or more items and item attributes by accessing every item in a table or a secondary index. The total number of scanned items has a maximum size limit of 1 MB. Scan operations proceed sequentially; however, for faster performance on a large table or secondary index, applications can request a parallel Scan operation. Scan uses eventually consistent reads when accessing the data in a table; therefore, the result set might not include the changes to data in the table immediately before the operation began. If you need a consistent copy [...]