Move caffeine out of extension and make it the default cache implementation.

distribution/pom.xml

@@ -79,8 +79,6 @@
                                 <argument>-c</argument>
                                 <argument>io.druid.extensions:druid-avro-extensions</argument>
                                 <argument>-c</argument>
-                                <argument>io.druid.extensions:druid-caffeine-cache</argument>
-                                <argument>-c</argument>
                                 <argument>io.druid.extensions:druid-datasketches</argument>
                                 <argument>-c</argument>
                                 <argument>io.druid.extensions:druid-hdfs-storage</argument>

docs/_redirects.json

@@ -113,5 +113,6 @@
   {"source": "tutorials/tutorial-all-about-queries.html", "target": "quickstart.html"},
   {"source": "tutorials/tutorial-loading-batch-data.html", "target": "tutorial-batch.html"},
   {"source": "tutorials/tutorial-loading-streaming-data.html", "target": "tutorial-streams.html"},
-  {"source": "tutorials/tutorial-the-druid-cluster.html", "target": "cluster.html"}
+  {"source": "tutorials/tutorial-the-druid-cluster.html", "target": "cluster.html"},
+  {"source": "development/extensions-core/caffeine-cache.html", "target":"../../configuration/caching.html"}
 ]

docs/content/configuration/caching.md

@@ -24,6 +24,12 @@ for both broker and historical nodes, when defined in the common properties file
 
 #### Local Cache
 
+<div class="note caution">
+DEPRECATED: Use caffeine instead
+</div>
+
+The local cache is deprecated in favor of the Caffeine cache, and may be removed in a future version of Druid. The Caffeine cache affords significantly better performance and control over eviction behavior compared to `local` cache, and is recommended in any situation where you are using JRE 8u60 or higher.
+
 A simple in-memory LRU cache. Local cache resides in JVM heap memory, so if you enable it, make sure you increase heap size accordingly.
 
 |Property|Description|Default|
@@ -32,6 +38,39 @@ A simple in-memory LRU cache. Local cache resides in JVM heap memory, so if you
 |`druid.cache.initialSize`|Initial size of the hashtable backing the cache.|500000|
 |`druid.cache.logEvictionCount`|If non-zero, log cache eviction every `logEvictionCount` items.|0|
 
+### Caffeine Cache
+
+A highly performant local cache implementation for Druid based on [Caffeine](https://github.com/ben-manes/caffeine). Requires a JRE8u60 or higher if using `COMMON_FJP`.
+
+##### Configuration
+
+Below are the configuration options known to this module:
+
+|`runtime.properties`|Description|Default|
+|--------------------|-----------|-------|
+|`druid.cache.type`| Set this to `caffeine`|`local`|
+|`druid.cache.sizeInBytes`|The maximum size of the cache in bytes on heap.|None (unlimited)|
+|`druid.cache.expireAfter`|The time (in ms) after an access for which a cache entry may be expired|None (no time limit)|
+|`druid.cache.cacheExecutorFactory`|The executor factory to use for Caffeine maintenance. One of `COMMON_FJP`, `SINGLE_THREAD`, or `SAME_THREAD`|ForkJoinPool common pool (`COMMON_FJP`)|
+|`druid.cache.evictOnClose`|If a close of a namespace (ex: removing a segment from a node) should cause an eager eviction of associated cache values|`false`|
+
+##### `druid.cache.cacheExecutorFactory`
+
+Here are the possible values for `druid.cache.cacheExecutorFactory`, which controls how maintenance tasks are run
+
+* `COMMON_FJP` (default) use the common ForkJoinPool. Should use with [JRE 8u60 or higher](https://github.com/druid-io/druid/pull/4810#issuecomment-329922810). Older versions of the JRE may have worse performance than newer JRE versions.
+* `SINGLE_THREAD` Use a single-threaded executor.
+* `SAME_THREAD` Cache maintenance is done eagerly.
+
+#### Metrics
+In addition to the normal cache metrics, the caffeine cache implementation also reports the following in both `total` and `delta`
+
+|Metric|Description|Normal value|
+|------|-----------|------------|
+|`query/cache/caffeine/*/requests`|Count of hits or misses|hit + miss|
+|`query/cache/caffeine/*/loadTime`|Length of time caffeine spends loading new values (unused feature)|0|
+|`query/cache/caffeine/*/evictionBytes`|Size in bytes that have been evicted from the cache|Varies, should tune cache `sizeInBytes` so that `sizeInBytes`/`evictionBytes` is approximately the rate of cache churn you desire|
+
 
 #### Memcached
 

pom.xml

@@ -79,6 +79,7 @@
         <!-- Cannot update to AWS SDK 1.11+ because of Jackson incompatibility.
         Need to update Druid to use Jackson 2.6+ -->
         <aws.sdk.version>1.10.77</aws.sdk.version>
+        <caffeine.version>2.5.5</caffeine.version>
     </properties>
 
     <modules>
@@ -100,7 +101,6 @@
         <module>hll</module>
         <!-- Core extensions -->
         <module>extensions-core/avro-extensions</module>
-        <module>extensions-core/caffeine-cache</module>
         <module>extensions-core/datasketches</module>
         <module>extensions-core/druid-kerberos</module>
         <module>extensions-core/hdfs-storage</module>
@@ -744,6 +744,11 @@
                 <version>${calcite.version}</version>
                 <type>test-jar</type>
             </dependency>
+            <dependency>
+                <groupId>com.github.ben-manes.caffeine</groupId>
+                <artifactId>caffeine</artifactId>
+                <version>${caffeine.version}</version>
+            </dependency>
             <dependency>
                 <groupId>org.easymock</groupId>
                 <artifactId>easymock</artifactId>

server/pom.xml

@@ -185,6 +185,10 @@
             <groupId>it.unimi.dsi</groupId>
             <artifactId>fastutil</artifactId>
         </dependency>
+        <dependency>
+            <groupId>com.github.ben-manes.caffeine</groupId>
+            <artifactId>caffeine</artifactId>
+        </dependency>
 
         <!-- Tests -->
         <dependency>

server/src/main/java/io/druid/client/cache/CacheProvider.java

@@ -23,11 +23,12 @@
 import com.fasterxml.jackson.annotation.JsonTypeInfo;
 import com.google.inject.Provider;
 
-@JsonTypeInfo(use = JsonTypeInfo.Id.NAME, property = "type", defaultImpl = LocalCacheProvider.class)
+@JsonTypeInfo(use = JsonTypeInfo.Id.NAME, property = "type", defaultImpl = CaffeineCacheProvider.class)
 @JsonSubTypes(value = {
     @JsonSubTypes.Type(name = "local", value = LocalCacheProvider.class),
     @JsonSubTypes.Type(name = "memcached", value = MemcachedCacheProvider.class),
-    @JsonSubTypes.Type(name = "hybrid", value = HybridCacheProvider.class)
+    @JsonSubTypes.Type(name = "hybrid", value = HybridCacheProvider.class),
+    @JsonSubTypes.Type(name = "caffeine", value = CaffeineCacheProvider.class)
 })
 public interface CacheProvider extends Provider<Cache>
 {

extensions-core/caffeine-cache/src/main/java/io/druid/client/cache/CaffeineCacheProvider.java → server/src/main/java/io/druid/client/cache/CaffeineCacheProvider.java

@@ -19,9 +19,6 @@
 
 package io.druid.client.cache;
 
-import com.fasterxml.jackson.annotation.JsonTypeName;
-
-@JsonTypeName("caffeine")
 public class CaffeineCacheProvider extends CaffeineCacheConfig implements CacheProvider
 {
   @Override

server/src/main/java/io/druid/client/cache/LocalCacheProvider.java

@@ -24,7 +24,9 @@
 import javax.validation.constraints.Min;
 
 /**
+ * Deprecated, use {@CaffeineCacheProvider}
  */
+@Deprecated
 public class LocalCacheProvider implements CacheProvider
 {
   @JsonProperty