OAK-12239: Remove FT_PREFETCH_OAK-9780 and remove 'no prefetch' code path

oak-doc/src/site/markdown/query/hybrid-index.md

@@ -57,7 +57,7 @@ For such use-cases, it's required that indexes are synchronous and results provi
 ### <a name="drawbacks-of-current-property-indexes"></a>Drawbacks of current property indexes
 Oak has support for synchronous property indexes, which are used to meet above use-cases. However the current implementation has certain drawbacks:
 
-* Slow reads over remote storage - The property indexes are stores as normal NodeState and hence reading them over remote storage like Mongo performs poorly (with Prefetch, OAK-9780, this is improved).
+* Slow reads over remote storage - The property indexes are stores as normal NodeState and hence reading them over remote storage like Mongo performs poorly (with Prefetch, this is now improved).
 * Storage overhead - The final storage overhead is larger, specially for remote storage where each NodeState is mapped to 1 document. (On the other hand, temporary disk usage for Lucene indexes might be higher than for node stores, due to write amplification with Lucene.)
  ---
 ### <a name="proposal"></a>Proposal

oak-lucene/src/test/java/org/apache/jackrabbit/oak/composite/PrefetchTest.java

@@ -36,18 +36,13 @@
 import javax.jcr.query.RowIterator;
 
 import org.apache.jackrabbit.api.JackrabbitSession;
-import org.apache.jackrabbit.oak.commons.junit.TemporarySystemProperty;
-import org.apache.jackrabbit.oak.plugins.document.DocumentNodeStore;
 import org.apache.jackrabbit.oak.plugins.document.prefetch.CacheWarming;
 import org.apache.jackrabbit.oak.spi.mount.MountInfoProvider;
 import org.apache.jackrabbit.oak.spi.mount.Mounts;
 import org.apache.jackrabbit.oak.spi.state.NodeStore;
 import org.junit.After;
 import org.junit.Before;
-import org.junit.Rule;
 import org.junit.Test;
-import org.junit.contrib.java.lang.system.ProvideSystemProperty;
-import org.junit.contrib.java.lang.system.RestoreSystemProperties;
 import org.junit.runners.Parameterized.Parameters;
 import org.slf4j.LoggerFactory;
 
@@ -80,21 +75,10 @@ public static Collection<Object[]> data() {
     private final String cacheWarmingLogger = CacheWarming.class.getName();
 
 
-    @Rule
-    public final ProvideSystemProperty updateSystemProperties
-            = new ProvideSystemProperty(DocumentNodeStore.SYS_PROP_PREFETCH, "true");
-
-    @Rule
-    public final RestoreSystemProperties restoreSystemProperties
-            = new RestoreSystemProperties();
-
     public PrefetchTest(NodeStoreKind root, NodeStoreKind mounts) {
         super(root, mounts);
     }
 
-    @Rule
-    public TemporarySystemProperty temporarySystemProperty = new TemporarySystemProperty();
-
     @Before
     public void loggingAppenderStart() {
         LoggerContext context = (LoggerContext) LoggerFactory.getILoggerFactory();

oak-store-document/AGENTS.md

@@ -318,9 +318,7 @@ every 10 `create` calls.
 ## Prefetch
 
 `PrefetchDispatcher` pre-fetches visible external changes in a background thread before delivery
-to local observers, hiding MongoDB/RDB read latency during observer dispatch. Controlled by
-feature toggle `FT_PREFETCH_OAK-9780` (disabled by default); wired via
-`DocumentNodeStoreBuilder.setPrefetchFeature()`.
+to local observers, hiding MongoDB/RDB read latency during observer dispatch.
 
 ## Persistent Cache
 
@@ -354,7 +352,6 @@ Registered in `DocumentNodeStoreService`, wired into `DocumentNodeStoreBuilder`.
 
 | Toggle name | Builder method | Purpose |
 |---|---|---|
-| `FT_PREFETCH_OAK-9780` | `setPrefetchFeature` | Enable async pre-fetching of external changes |
 | `FT_THROTTLING_OAK-9909` | `setDocStoreThrottlingFeature` | Enable write throttling on MongoDB |
 | `FT_DISABLE_THROTTLING_OAK-12119` | `setDocStoreDisableThrottlingFeature` | Runtime kill-switch to disable throttling |
 | `FT_NOCOCLEANUP_OAK-10660` | `setNoChildOrderCleanupFeature` | Disable child-order property cleanup |

oak-store-document/src/main/java/org/apache/jackrabbit/oak/plugins/document/DocumentNodeStore.java

@@ -216,9 +216,6 @@
     static final long DEFAULT_MAX_SERVER_TIME_DIFFERENCE = 2000L;
     private final long maxTimeDiffMillis = SystemPropertySupplier.create("oak.documentMK.maxServerTimeDiffMillis", DEFAULT_MAX_SERVER_TIME_DIFFERENCE).loggingTo(LOG).get();
 
-    public static final String SYS_PROP_PREFETCH = "oak.documentstore.prefetch";
-    private final boolean prefetchEnabled = SystemPropertySupplier.create(SYS_PROP_PREFETCH, false).loggingTo(LOG).get();
-
     /**
      * The document store without potentially lease checking wrapper.
      */
@@ -559,8 +556,6 @@
 
     private final Predicate<Path> nodeCachePredicate;
 
-    private final Feature prefetchFeature;
-
     private final Feature cancelInvalidationFeature;
 
     private final Feature noChildOrderCleanupFeature;
@@ -640,7 +635,6 @@
             leaseUpdateThread.start();
         }
 
-        this.prefetchFeature = builder.getPrefetchFeature();
         this.cancelInvalidationFeature = builder.getCancelInvalidationFeature();
         this.noChildOrderCleanupFeature = builder.getNoChildOrderCleanupFeature();
         this.avoidMergeLock = isAvoidMergeLockEnabled(builder);
@@ -1657,7 +1651,7 @@
      * @param changed the list of changed child nodes
      *
      */
     void applyChanges(RevisionVector before, RevisionVector after,
                       Revision rev, Path path,
                       boolean isNew, List<Path> added,
                       List<Path> removed, List<Path> changed) {
@@ -4046,18 +4040,11 @@
     @Override
     public void prefetch(java.util.Collection<String> paths, NodeState rootState) {
         if (paths != null
-                && rootState instanceof DocumentNodeState
-                && isPrefetchEnabled()) {
-            cacheWarming.prefetch(paths, (DocumentNodeState) rootState);
+                && rootState instanceof DocumentNodeState documentNodeState) {
+            cacheWarming.prefetch(paths, documentNodeState);
         }
     }
 
-    private boolean isPrefetchEnabled() {
-        // feature can be enabled with system property or feature toggle
-        return prefetchEnabled
-                || (prefetchFeature != null && prefetchFeature.isEnabled());
-    }
-
     /**
      * Configures the performance logger with the specified info log interval.
      *

oak-store-document/src/main/java/org/apache/jackrabbit/oak/plugins/document/DocumentNodeStoreBuilder.java

@@ -39,7 +39,6 @@
 import org.apache.jackrabbit.oak.cache.api.Cache;
 import org.apache.jackrabbit.oak.cache.api.CacheBuilder;
 import org.apache.jackrabbit.oak.cache.api.CacheStatsAdapter;
-import org.apache.jackrabbit.oak.cache.api.EvictionCause;
 import org.apache.jackrabbit.oak.cache.api.Weigher;
 import org.apache.jackrabbit.oak.cache.AbstractCacheStats;
 import org.apache.jackrabbit.oak.cache.CacheValue;
@@ -128,7 +127,6 @@ public class DocumentNodeStoreBuilder<T extends DocumentNodeStoreBuilder<T>> {
     private String loggingPrefix;
     private LeaseCheckMode leaseCheck = ClusterNodeInfo.DEFAULT_LEASE_CHECK_MODE; // OAK-2739 is enabled by default also for non-osgi
     private boolean isReadOnlyMode = false;
-    private Feature prefetchFeature;
     private Feature docStoreThrottlingFeature;
     private Feature noChildOrderCleanupFeature;
     private Feature cancelInvalidationFeature;
@@ -466,16 +464,6 @@ public boolean getReadOnlyMode() {
         return isReadOnlyMode;
     }
 
-    public T setPrefetchFeature(@Nullable Feature prefetch) {
-        this.prefetchFeature = prefetch;
-        return thisBuilder();
-    }
-
-    @Nullable
-    public Feature getPrefetchFeature() {
-        return prefetchFeature;
-    }
-
     public T setDocStoreThrottlingFeature(@Nullable Feature docStoreThrottling) {
         this.docStoreThrottlingFeature = docStoreThrottling;
         return thisBuilder();

oak-store-document/src/main/java/org/apache/jackrabbit/oak/plugins/document/DocumentNodeStoreService.java

@@ -197,11 +197,6 @@ public class DocumentNodeStoreService {
      */
     static final long DEFAULT_BLOB_SNAPSHOT_INTERVAL = 12 * 60 * 60;
 
-    /**
-     * Feature toggle name to enable prefetch operation in DocumentStore
-     */
-    private static final String FT_NAME_PREFETCH = "FT_PREFETCH_OAK-9780";
-
     /**
      * Feature toggle name to enable document store throttling for Mongo Document Store
      */
@@ -276,7 +271,6 @@ static DocumentStoreType fromString(String type) {
     private DocumentNodeStore nodeStore;
     private ObserverTracker observerTracker;
     private JournalPropertyHandlerFactory journalPropertyHandlerFactory = new JournalPropertyHandlerFactory();
-    private Feature prefetchFeature;
     private Feature docStoreThrottlingFeature;
     private Feature noChildOrderCleanupFeature;
     private Feature cancelInvalidationFeature;
@@ -316,7 +310,6 @@ protected void activate(ComponentContext context, Configuration config) throws E
         executor.start(whiteboard);
         customBlobStore = this.config.customBlobStore();
         documentStoreType = DocumentStoreType.fromString(this.config.documentStoreType());
-        prefetchFeature = Feature.newFeature(FT_NAME_PREFETCH, whiteboard);
         docStoreThrottlingFeature = Feature.newFeature(FT_NAME_DOC_STORE_THROTTLING, whiteboard);
         noChildOrderCleanupFeature = Feature.newFeature(FT_NAME_DOC_STORE_NOCOCLEANUP, whiteboard);
         cancelInvalidationFeature = Feature.newFeature(FT_NAME_CANCEL_INVALIDATION, whiteboard);
@@ -554,7 +547,6 @@ private void configureBuilder(DocumentNodeStoreBuilder<?> builder) {
                 setBundlingDisabled(config.bundlingDisabled()).
                 setJournalPropertyHandlerFactory(journalPropertyHandlerFactory).
                 setLeaseCheckMode(ClusterNodeInfo.DEFAULT_LEASE_CHECK_DISABLED ? LeaseCheckMode.DISABLED : LeaseCheckMode.valueOf(config.leaseCheckMode())).
-                setPrefetchFeature(prefetchFeature).
                 setDocStoreThrottlingFeature(docStoreThrottlingFeature).
                 setNoChildOrderCleanupFeature(noChildOrderCleanupFeature).
                 setCancelInvalidationFeature(cancelInvalidationFeature).
@@ -720,7 +712,7 @@ protected void deactivate() {
             journalPropertyHandlerFactory.stop();
         }
 
-        closeFeatures(prefetchFeature, docStoreThrottlingFeature, cancelInvalidationFeature, docStoreFullGCFeature,
+        closeFeatures(docStoreThrottlingFeature, cancelInvalidationFeature, docStoreFullGCFeature,
                 docStoreEmbeddedVerificationFeature, prevNoPropCacheFeature, docStoreAvoidMergeLockFeature);
 
         unregisterNodeStore();

oak-store-document/src/test/java/org/apache/jackrabbit/oak/plugins/document/ConcurrentPrefetchAndUpdateIT.java

@@ -30,7 +30,6 @@
 import org.apache.jackrabbit.oak.plugins.document.util.Utils;
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
-import org.junit.After;
 import org.junit.Before;
 import org.junit.Test;
 
@@ -53,7 +52,6 @@ public class ConcurrentPrefetchAndUpdateIT extends AbstractMongoConnectionTest {
     @Before
     @Override
     public void setUpConnection() throws Exception {
-        System.setProperty(DocumentNodeStore.SYS_PROP_PREFETCH, String.valueOf(true));
         mongoConnection = connectionFactory.getConnection();
         assertNotNull(mongoConnection);
         MongoDatabase db = mongoConnection.getDatabase();
@@ -64,11 +62,6 @@ public void setUpConnection() throws Exception {
         mk = builder.setDocumentStore(store).open();
     }
 
-    @After
-    public void clearSystemProperty() {
-        System.clearProperty(DocumentNodeStore.SYS_PROP_PREFETCH);
-    }
-
     @Test
     public void cacheConsistency() throws Exception {
         Revision r = newRevision();

oak-store-document/src/test/java/org/apache/jackrabbit/oak/plugins/document/prefetch/CacheWarmingTest.java

@@ -16,7 +16,6 @@
  */
 package org.apache.jackrabbit.oak.plugins.document.prefetch;
 
-import static org.apache.jackrabbit.oak.plugins.document.DocumentNodeStore.SYS_PROP_PREFETCH;
 import static org.apache.jackrabbit.oak.plugins.document.util.Utils.getIdFromPath;
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertNotNull;
@@ -34,7 +33,6 @@
 
 import com.mongodb.MongoTimeoutException;
 import org.apache.jackrabbit.oak.api.CommitFailedException;
-import org.apache.jackrabbit.oak.commons.junit.TemporarySystemProperty;
 import org.apache.jackrabbit.oak.commons.time.Stopwatch;
 import org.apache.jackrabbit.oak.plugins.document.Collection;
 import org.apache.jackrabbit.oak.plugins.document.CountingDocumentStore;
@@ -55,17 +53,13 @@
 import org.apache.jackrabbit.oak.stats.Clock;
 import org.jetbrains.annotations.Nullable;
 import org.junit.AfterClass;
-import org.junit.Before;
 import org.junit.Rule;
 import org.junit.Test;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
 public class CacheWarmingTest {
 
-    @Rule
-    public TemporarySystemProperty systemProperties = new TemporarySystemProperty();
-
     @Rule
     public DocumentMKBuilderProvider builderProvider = new DocumentMKBuilderProvider();
 
@@ -78,11 +72,6 @@ public class CacheWarmingTest {
 
     private CountingMongoDatabase db;
 
-    @Before
-    public void enablePrefetch() {
-        System.setProperty(SYS_PROP_PREFETCH, "true");
-    }
-
     @AfterClass
     public static void cleanUp() {
         MongoUtils.dropCollections(MongoUtils.DB);