RedisCommandTimeout Exception when executing Redis commands synchronously.

[raiden99]

My use case is very simple, I'm caching the result of a REST API in Elasticache Redis in a clustered setup. Since this is a blocking call I'm using synchronous Redis commands. Below is the stack trace. I have enabled DEBUG logs for io.lettuce.core and have not noticed any commands being queued up. Any ideas as to how I can debug this issue? I'm using lettuce-core 6.1.5.RELEASE. Request rate for my server is 3000 request/sec and I'm using a connection pool with

min-idle-connections = 1
max-idle-connections = 10
max-total-connections = 100

I have also enabled the lettuce command latency metrics and the slowest GET and SET do not exceed 0.05 seconds.

io.lettuce.core.RedisCommandTimeoutException: Command timed out after 500 millisecond(s) at io.lettuce.core.internal.ExceptionFactory.createTimeoutException(ExceptionFactory.java:59) at io.lettuce.core.internal.Futures.awaitOrCancel(Futures.java:246) at io.lettuce.core.cluster.ClusterFutureSyncInvocationHandler.handleInvocation(ClusterFutureSyncInvocationHandler.java:131) at io.lettuce.core.internal.AbstractInvocationHandler.invoke(AbstractInvocationHandler.java:80) at jdk.internal.reflect.GeneratedMethodAccessor183.invoke(Unknown Source) [1 skipped] Wrapped by: java.util.concurrent.CompletionException: io.lettuce.core.RedisCommandTimeoutException: Command timed out after 500 millisecond(s) at java.base/java.util.concurrent.CompletableFuture.encodeThrowable(CompletableFuture.java:314) at java.base/java.util.concurrent.CompletableFuture.completeThrowable(CompletableFuture.java:319) at java.base/java.util.concurrent.CompletableFuture$AsyncSupply.run(CompletableFuture.java:1702) at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1128) at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:628)