Align default values for Cassandra's throttling properties

Closes gh-25149

Author: snicoll

spring-boot-project/spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/cassandra/CassandraProperties.java

@@ -356,24 +356,24 @@ public static class Throttler {
 		 * Maximum number of requests that can be enqueued when the throttling threshold
 		 * is exceeded.
 		 */
-		private int maxQueueSize = 10000;
+		private int maxQueueSize;
 
 		/**
 		 * Maximum number of requests that are allowed to execute in parallel.
 		 */
-		private int maxConcurrentRequests = 10000;
+		private int maxConcurrentRequests;
 
 		/**
 		 * Maximum allowed request rate.
 		 */
-		private int maxRequestsPerSecond = 10000;
+		private int maxRequestsPerSecond;
 
 		/**
 		 * How often the throttler attempts to dequeue requests. Set this high enough that
 		 * each attempt will process multiple entries in the queue, but not delay requests
 		 * too much.
 		 */
-		private Duration drainInterval = Duration.ofMillis(10);
+		private Duration drainInterval;
 
 		public ThrottlerType getType() {
 			return this.type;

spring-boot-project/spring-boot-autoconfigure/src/test/java/org/springframework/boot/autoconfigure/cassandra/CassandraAutoConfigurationTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2020 the original author or authors.
+ * Copyright 2012-2021 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -17,6 +17,7 @@
 package org.springframework.boot.autoconfigure.cassandra;
 
 import com.datastax.oss.driver.api.core.CqlIdentifier;
+import com.datastax.oss.driver.api.core.CqlSession;
 import com.datastax.oss.driver.api.core.CqlSessionBuilder;
 import com.datastax.oss.driver.api.core.config.DefaultDriverOption;
 import com.datastax.oss.driver.api.core.config.DriverConfigLoader;
@@ -32,6 +33,7 @@
 import org.springframework.context.annotation.Configuration;
 
 import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.assertThatThrownBy;
 
 /**
  * Tests for {@link CassandraAutoConfiguration}
@@ -186,6 +188,14 @@ void driverConfigLoaderUsePassThroughLimitingRequestThrottlerByDefault() {
 		});
 	}
 
+	@Test
+	void driverConfigLoaderWithRateLimitingRequiresExtraConfiguration() {
+		this.contextRunner.withPropertyValues("spring.data.cassandra.request.throttler.type=rate-limiting")
+				.run((context) -> assertThatThrownBy(() -> context.getBean(CqlSession.class))
+						.hasMessageContaining("Error instantiating class RateLimitingRequestThrottler")
+						.hasMessageContaining("No configuration setting found for key"));
+	}
+
 	@Test
 	void driverConfigLoaderCustomizeConcurrencyLimitingRequestThrottler() {
 		this.contextRunner.withPropertyValues("spring.data.cassandra.request.throttler.type=concurrency-limiting",