Moved keystore to the ehcache plugin

Signed-off-by: Peter Alfonsi <[email protected]>

plugins/cache-ehcache/build.gradle

@@ -18,7 +18,12 @@ opensearchplugin {
 }
 
 dependencies {
+  // for ehcache
   api "org.ehcache:ehcache:${versions.ehcache}"
+
+  // For roaring bitmaps
+  api 'org.roaringbitmap:RoaringBitmap:0.9.49'
+  runtimeOnly 'org.roaringbitmap:shims:0.9.49'
 }
 
 thirdPartyAudit {

plugins/cache-ehcache/src/main/java/org/opensearch/cache/EhcacheDiskCache.java

@@ -11,6 +11,7 @@
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 import org.opensearch.OpenSearchException;
+import org.opensearch.cache.keystore.RBMIntKeyLookupStore;
 import org.opensearch.common.SuppressForbidden;
 import org.opensearch.common.annotation.ExperimentalApi;
 import org.opensearch.common.cache.LoadAwareCacheLoader;
@@ -23,6 +24,7 @@
 import org.opensearch.common.cache.store.config.StoreAwareCacheConfig;
 import org.opensearch.common.cache.store.enums.CacheStoreType;
 import org.opensearch.common.cache.store.listeners.StoreAwareCacheEventListener;
+import org.opensearch.common.cache.tier.keystore.KeyLookupStore;
 import org.opensearch.common.collect.Tuple;
 import org.opensearch.common.metrics.CounterMetric;
 import org.opensearch.common.settings.Settings;
@@ -61,6 +63,8 @@
 import static org.opensearch.cache.EhcacheSettings.DISK_WRITE_CONCURRENCY;
 import static org.opensearch.cache.EhcacheSettings.DISK_WRITE_MAXIMUM_THREADS;
 import static org.opensearch.cache.EhcacheSettings.DISK_WRITE_MINIMUM_THREADS;
+import static org.opensearch.cache.EhcacheSettings.RBM_KEYSTORE_SIZE;
+import static org.opensearch.cache.EhcacheSettings.USE_RBM_KEYSTORE;
 
 /**
  * This variant of disk cache uses Ehcache underneath.
@@ -111,6 +115,8 @@ public class EhcacheDiskCache<K, V> implements StoreAwareCache<K, V> {
      */
     Map<K, CompletableFuture<Tuple<K, V>>> completableFutureMap = new ConcurrentHashMap<>();
 
+    KeyLookupStore<Integer> keystore = null;
+
     private EhcacheDiskCache(Builder<K, V> builder) {
         this.keyType = Objects.requireNonNull(builder.keyType, "Key type shouldn't be null");
         this.valueType = Objects.requireNonNull(builder.valueType, "Value type shouldn't be null");
@@ -131,6 +137,10 @@ private EhcacheDiskCache(Builder<K, V> builder) {
         this.eventListener = builder.getEventListener();
         this.ehCacheEventListener = new EhCacheEventListener<K, V>(builder.getEventListener());
         this.cache = buildCache(Duration.ofMillis(expireAfterAccess.getMillis()), builder);
+        if (USE_RBM_KEYSTORE.get(settings)) {
+            long keystoreSize = RBM_KEYSTORE_SIZE.get(settings).getBytes();
+            this.keystore = new RBMIntKeyLookupStore(keystoreSize);
+        }
     }
 
     private Cache<K, V> buildCache(Duration expireAfterAccess, Builder<K, V> builder) {
@@ -216,11 +226,13 @@ public V get(K key) {
         if (key == null) {
             throw new IllegalArgumentException("Key passed to ehcache disk cache was null.");
         }
-        V value;
-        try {
-            value = cache.get(key);
-        } catch (CacheLoadingException ex) {
-            throw new OpenSearchException("Exception occurred while trying to fetch item from ehcache disk cache");
+        V value = null;
+        if (keystore == null || keystore.contains(key.hashCode()) || keystore.isFull()) {
+            try {
+                value = cache.get(key);
+            } catch (CacheLoadingException ex) {
+                throw new OpenSearchException("Exception occurred while trying to fetch item from ehcache disk cache");
+            }
         }
         if (value != null) {
             eventListener.onHit(key, value, CacheStoreType.DISK);
@@ -239,6 +251,9 @@ public V get(K key) {
     public void put(K key, V value) {
         try {
             cache.put(key, value);
+            if (keystore != null) {
+                keystore.add(key.hashCode());
+            }
         } catch (CacheWritingException ex) {
             throw new OpenSearchException("Exception occurred while put item to ehcache disk cache");
         }

plugins/cache-ehcache/src/main/java/org/opensearch/cache/EhcacheSettings.java

@@ -9,6 +9,7 @@
 package org.opensearch.cache;
 
 import org.opensearch.common.settings.Setting;
+import org.opensearch.core.common.unit.ByteSizeValue;
 
 /**
  * Settings related to ehcache.
@@ -45,6 +46,20 @@ public class EhcacheSettings {
      */
     public static final Setting<Integer> DISK_SEGMENTS = Setting.intSetting(SETTING_PREFIX + ".segments", 16, 1, 32);
 
+    /**
+     * Defines whether to use an in-memory keystore to check for probable presence of keys before having to go to disk.
+     */
+    public static final Setting<Boolean> USE_RBM_KEYSTORE = Setting.boolSetting(SETTING_PREFIX + ".use_keystore", true);
+
+    /**
+     * Defines the max size of the RBM keystore if used (as a percentage of heap memory)
+     */
+    public static final Setting<ByteSizeValue> RBM_KEYSTORE_SIZE = Setting.memorySizeSetting(
+        SETTING_PREFIX + ".keystore_size",
+        "0.05%",
+        Setting.Property.Dynamic
+    );
+
     /**
      * Default constructor. Added to fix javadocs.
      */

modules/roaringbitmap-keystore/src/main/java/org/opensearch/cache/KeyStoreStats.java → plugins/cache-ehcache/src/main/java/org/opensearch/cache/keystore/KeyStoreStats.java

@@ -6,7 +6,7 @@
  * compatible open source license.
  */
 
-package org.opensearch.cache;
+package org.opensearch.cache.keystore;
 
 import org.opensearch.common.metrics.CounterMetric;
 

modules/roaringbitmap-keystore/src/main/java/org/opensearch/cache/RBMIntKeyLookupStore.java → plugins/cache-ehcache/src/main/java/org/opensearch/cache/keystore/RBMIntKeyLookupStore.java

@@ -6,7 +6,7 @@
  * compatible open source license.
  */
 
-package org.opensearch.cache;
+package org.opensearch.cache.keystore;
 
 import org.opensearch.common.cache.tier.keystore.KeyLookupStore;
 import org.opensearch.common.metrics.CounterMetric;

modules/roaringbitmap-keystore/src/test/java/org/opensearch/cache/RBMIntKeyLookupStoreTests.java → plugins/cache-ehcache/src/test/java/org/opensearch/cache/keystore/RBMIntKeyLookupStoreTests.java

@@ -6,7 +6,7 @@
  * compatible open source license.
  */
 
-package org.opensearch.cache;
+package org.opensearch.cache.keystore;
 
 import org.opensearch.common.Randomness;
 import org.opensearch.common.metrics.CounterMetric;