ATLAS-3417 Improve Atlas Initialization Performance for fresh installation.

repository/src/main/java/org/apache/atlas/repository/graph/GraphBackedSearchIndexer.java

@@ -126,6 +126,7 @@ public class GraphBackedSearchIndexer implements SearchIndexer, ActiveStateChang
         if (!HAConfiguration.isHAEnabled(configuration)) {
             initialize(provider.get());
         }
+        notifyInitializationStart();
     }
 
     public void addIndexListener(IndexChangeListener listener) {
@@ -221,7 +222,7 @@ public class GraphBackedSearchIndexer implements SearchIndexer, ActiveStateChang
             //Commit indexes
             commit(management);
 
-            notifyChangeListeners(changedTypeDefs);
+            notifyInitializationCompletion(changedTypeDefs);
         } catch (RepositoryException | IndexException e) {
             LOG.error("Failed to update indexes for changed typedefs", e);
             attemptRollback(changedTypeDefs, management);
@@ -967,4 +968,28 @@ public class GraphBackedSearchIndexer implements SearchIndexer, ActiveStateChang
         }
     }
 
+    private void notifyInitializationStart() {
+        for (IndexChangeListener indexChangeListener : indexChangeListeners) {
+            try {
+                indexChangeListener.onInitStart();
+            } catch (Throwable t) {
+                LOG.error("Error encountered in notifying the index change listener {}.", indexChangeListener.getClass().getName(), t);
+                //we need to throw exception if any of the listeners throw execption.
+                throw new RuntimeException("Error encountered in notifying the index change listener " + indexChangeListener.getClass().getName(), t);
+            }
+        }
+    }
+
+    private void notifyInitializationCompletion(ChangedTypeDefs changedTypeDefs) {
+        for (IndexChangeListener indexChangeListener : indexChangeListeners) {
+            try {
+                indexChangeListener.onInitCompletion(changedTypeDefs);
+            } catch (Throwable t) {
+                LOG.error("Error encountered in notifying the index change listener {}.", indexChangeListener.getClass().getName(), t);
+                //we need to throw exception if any of the listeners throw execption.
+                throw new RuntimeException("Error encountered in notifying the index change listener " + indexChangeListener.getClass().getName(), t);
+            }
+        }
+    }
+
 }

repository/src/main/java/org/apache/atlas/repository/graph/IndexChangeListener.java

@@ -21,4 +21,6 @@ import org.apache.atlas.listener.ChangedTypeDefs;
 
 public interface IndexChangeListener {
     void onChange(ChangedTypeDefs changedTypeDefs);
+    void onInitStart();
+    void onInitCompletion(ChangedTypeDefs changedTypeDefs);
 }

repository/src/main/java/org/apache/atlas/repository/graph/SolrIndexHelper.java

@@ -58,6 +58,7 @@ public class SolrIndexHelper implements IndexChangeListener {
     public SolrIndexHelper(AtlasTypeRegistry typeRegistry) {
         this.typeRegistry = typeRegistry;
     }
+    public boolean initializationCompleted = false;
 
     @Override
     public void onChange(ChangedTypeDefs changedTypeDefs) {
@@ -65,7 +66,7 @@ public class SolrIndexHelper implements IndexChangeListener {
             changedTypeDefs == null || !changedTypeDefs.hasEntityDef()) { // nothing to do if there are no changes to entity-defs
             return;
         }
-
+        if(initializationCompleted) {
             try {
                 AtlasGraph            graph                          = AtlasGraphProvider.getGraphInstance();
                 AtlasGraphIndexClient graphIndexClient               = graph.getGraphIndexClient();
@@ -78,6 +79,20 @@ public class SolrIndexHelper implements IndexChangeListener {
                 throw new RuntimeException("Error encountered in handling type system change notification.", e);
             }
         }
+    }
+
+    @Override
+    public void onInitStart() {
+        LOG.info("SolrIndexHelper Initialization started.");
+        initializationCompleted = false;
+    }
+
+    @Override
+    public void onInitCompletion(ChangedTypeDefs changedTypeDefs) {
+        LOG.info("SolrIndexHelper Initialization completed.");
+        initializationCompleted = true;
+        onChange(changedTypeDefs);
+    }
 
     private List<String> getIndexFieldNamesForSuggestions(Map<String, Integer> indexFieldName2SearchWeightMap) {
         List<String> ret = new ArrayList<>();