DataStax-Examples/concurrent-requests-java

This example shows three different ways of handling concurrent request execution with Apache Cassandra™ using theJava DataStax Driver.Contributors: Olivier Michallat, Hsu-Kwang Hwang, Tomasz Lelek - derived fromhereObjectivesHow to limit concurrent query executions with Cassandra in blocking and non-blocking ways.How to throttle Concurrent Requests.Project LayoutThe following are the main Java files used by the application.LimitConcurrencyCustom - This example shows executing concurrent queries in blocking ways.The basic java concurrent mechanism such as SEMAPHORE, and Latch are used to control the flow.LimitConcurrencyCustomAsync - This example shows executing concurrent queries innon-blocking ways. Java CompletableFuture is used to achieve non-blocking.LimitConcurrencyRequestThrottler - Throttling allows you to limit how manyrequests a session can execute concurrently. This is useful if you have multiple applications connecting to the same Cassandra cluster, and want to enforce somekind of SLA to ensure fair resource allocation.Setup and RunningPrerequisitesMaven 3 installed on the machine running the examplesJDK 14An Apache Cassandra(R) cluster is running and accessible through the contacts points and data center identified in application.confRunningBuildingAt the project root levelmvn clean packageThis builds the JAR file located at target/java-concurrent-execution-1.0.jarConfiguration changesThe main configuration file is src/main/resources/application.confChange basic.contact-points = ["127.0.0.1:9042"] to the IP and cql port of your Cassandra cluster.Change basic.local-datacenter = dc1 to the datacenter of the Cassandra cluster you want to connect to.ThrottlingFor throttling the configurations are in the following blockadvanced.throttler { class = ConcurrencyLimitingRequestThrottler max-concurrent-requests = 32 max-queue-size = 10000}You are encouraged to experiment the configuration. For more details about throttling please check thefollowing linkRun the programjava -cp target/java-concurrent-execution-1.0.jar com.datastax.examples.LimitConcurrencyCustomjava -cp target/java-concurrent-execution-1.0.jar com.datastax.examples.LimitConcurrencyCustomAsyncjava -cp target/java-concurrent-execution-1.0.jar com.datastax.examples.LimitConcurrencyRequestThrottler