12.12 Performance Checklist

• Use a relay server to examine data transfers.

• Reduce the number of messages transferred.

  • Cache data and objects to change distributed requests to local ones.

  • Batch messages to reduce the number of messages transferred.

  • Compress large transfers.

  • Partition the application so that methods execute where their data is held.

  • Multiplex communications to reduce connection overhead.

  • Stub out data links to reduce the amount of data required to be transferred.

• Design the various components so that they can execute asynchronously from each other.

  • Anticipate data requirements so that data is transferred earlier.

  • Split up data so that partial results can be displayed.

  • Avoid creating distributed garbage.

• Optimize database communications. Application partitioning is especially important with databases.

  • Use statically defined database queries.

  • Avoid database transactional modes if possible.

  • Use JDBC optimizations such as prepared statements, specific SQL requests, etc.

• Try to break down the time to execute a Web Service into client, server, and network processing times, and extract the marshalling and unmarshalling times from client and server processing.

• Don't forget about DNS resolution time for a Web Service.

• Try to load-balance high-demand Web Services or provide them asynchronously.

• The granularity of a Web Service is important. For more scalable and better performing Web Services, create coarser services that require fewer network requests to complete.