to avoid memory leak drop merged data from disk on finishing every test / or on low memory

platform/lang-impl/src/com/intellij/util/indexing/FileBasedIndexImpl.java

@@ -943,6 +943,19 @@ public class FileBasedIndexImpl extends FileBasedIndex {
   @TestOnly
   public void cleanupForNextTest() {
     myTransactionMap = SmartFMap.emptyMap();
+    IndexConfiguration state = getState();
+    for (ID<?, ?> indexId : state.getIndexIDs()) {
+      final MapReduceIndex index = (MapReduceIndex)state.getIndex(indexId);
+      assert index != null;
+      final MemoryIndexStorage memStorage = (MemoryIndexStorage)index.getStorage();
+      index.getWriteLock().lock();
+      try {
+        memStorage.clearCaches();
+      }
+      finally {
+        index.getWriteLock().unlock();
+      }
+    }
   }
 
   @TestOnly

platform/lang-impl/src/com/intellij/util/indexing/MemoryIndexStorage.java

@@ -96,15 +96,19 @@ public class MemoryIndexStorage<Key, Value> implements VfsAwareIndexStorage<Key,
 
   @Override
   public void clearCaches() {
-    if (myMap.size() == 0) return;
+    try {
+      if (myMap.size() == 0) return;
 
-    if (DebugAssertions.DEBUG) {
-      String message = "Dropping caches for " + (myIndexId != null ? myIndexId:this) + ", number of items:" + myMap.size();
-      FileBasedIndexImpl.LOG.info(message);
-    }
+      if (DebugAssertions.DEBUG) {
+        String message = "Dropping caches for " + (myIndexId != null ? myIndexId : this) + ", number of items:" + myMap.size();
+        FileBasedIndexImpl.LOG.info(message);
+      }
 
-    for(ChangeTrackingValueContainer<Value> v:myMap.values()) {
-      v.dropMergedData();
+      for (ChangeTrackingValueContainer<Value> v : myMap.values()) {
+        v.dropMergedData();
+      }
+    } finally {
+      myBackendStorage.clearCaches();
     }
   }
 

platform/util/src/com/intellij/util/indexing/impl/MapIndexStorage.java

@@ -27,6 +27,7 @@ import org.jetbrains.annotations.TestOnly;
 
 import java.io.File;
 import java.io.IOException;
+import java.util.Map;
 import java.util.concurrent.locks.Lock;
 import java.util.concurrent.locks.ReentrantLock;
 
@@ -243,7 +244,14 @@ public abstract class MapIndexStorage<Key, Value> implements IndexStorage<Key, V
 
   @Override
   public void clearCaches() {
-
+    l.lock();
+    try {
+      for(Map.Entry<Key, ChangeTrackingValueContainer<Value>> entry:myCache.entrySet()) {
+        entry.getValue().dropMergedData();
+      }
+    } finally {
+      l.unlock();
+    }
   }
 
   protected static <T> T unwrapCauseAndRethrow(RuntimeException e) throws StorageException {