Removed index level metadata election #17233

When a master is elected, it reaches out to all master nodes for their cluster state, selecting the one with the highest version. At the moment, we do another round to select the index metadata with the highest version as well. This is not needed - the election of a cluster state is enough - we should just use whatever indices are in it.

Closes #17233

core/src/main/java/org/elasticsearch/gateway/Gateway.java

@@ -19,9 +19,6 @@
 
 package org.elasticsearch.gateway;
 
-import com.carrotsearch.hppc.ObjectFloatHashMap;
-import com.carrotsearch.hppc.ObjectHashSet;
-import com.carrotsearch.hppc.cursors.ObjectCursor;
 import org.apache.lucene.util.IOUtils;
 import org.elasticsearch.action.FailedNodeException;
 import org.elasticsearch.cluster.ClusterChangedEvent;
@@ -34,15 +31,11 @@ import org.elasticsearch.common.component.AbstractComponent;
 import org.elasticsearch.common.settings.Settings;
 import org.elasticsearch.discovery.Discovery;
 import org.elasticsearch.env.NodeEnvironment;
-import org.elasticsearch.index.Index;
-import org.elasticsearch.index.IndexService;
 import org.elasticsearch.index.NodeServicesProvider;
 import org.elasticsearch.indices.IndicesService;
 
-import java.io.IOException;
 import java.nio.file.Path;
 import java.util.Arrays;
-import java.util.Collections;
 import java.util.function.Supplier;
 
 /**
@@ -91,7 +84,6 @@ public class Gateway extends AbstractComponent implements ClusterStateListener {
             }
         }
 
-        ObjectFloatHashMap<Index> indices = new ObjectFloatHashMap<>();
         MetaData electedGlobalState = null;
         int found = 0;
         for (TransportNodesListGatewayMetaState.NodeGatewayMetaState nodeState : nodesState) {
@@ -104,65 +96,34 @@ public class Gateway extends AbstractComponent implements ClusterStateListener {
             } else if (nodeState.metaData().version() > electedGlobalState.version()) {
                 electedGlobalState = nodeState.metaData();
             }
-            for (ObjectCursor<IndexMetaData> cursor : nodeState.metaData().indices().values()) {
-                indices.addTo(cursor.value.getIndex(), 1);
-            }
         }
         if (found < requiredAllocation) {
             listener.onFailure("found [" + found + "] metadata states, required [" + requiredAllocation + "]");
             return;
         }
-        // update the global state, and clean the indices, we elect them in the next phase
-        MetaData.Builder metaDataBuilder = MetaData.builder(electedGlobalState).removeAllIndices();
-
-        assert !indices.containsKey(null);
-        final Object[] keys = indices.keys;
-        for (int i = 0; i < keys.length; i++) {
-            if (keys[i] != null) {
-                Index index = (Index) keys[i];
-                IndexMetaData electedIndexMetaData = null;
-                int indexMetaDataCount = 0;
-                for (TransportNodesListGatewayMetaState.NodeGatewayMetaState nodeState : nodesState) {
-                    if (nodeState.metaData() == null) {
-                        continue;
-                    }
-                    IndexMetaData indexMetaData = nodeState.metaData().index(index);
-                    if (indexMetaData == null) {
-                        continue;
-                    }
-                    if (electedIndexMetaData == null) {
-                        electedIndexMetaData = indexMetaData;
-                    } else if (indexMetaData.getVersion() > electedIndexMetaData.getVersion()) {
-                        electedIndexMetaData = indexMetaData;
-                    }
-                    indexMetaDataCount++;
-                }
-                if (electedIndexMetaData != null) {
-                    if (indexMetaDataCount < requiredAllocation) {
-                        logger.debug("[{}] found [{}], required [{}], not adding", index, indexMetaDataCount, requiredAllocation);
-                    } // TODO if this logging statement is correct then we are missing an else here
-                    try {
-                        if (electedIndexMetaData.getState() == IndexMetaData.State.OPEN) {
-                            // verify that we can actually create this index - if not we recover it as closed with lots of warn logs
-                            indicesService.verifyIndexMetadata(nodeServicesProvider, electedIndexMetaData);
-                        }
-                    } catch (Exception e) {
-                        logger.warn("recovering index {} failed - recovering as closed", e, electedIndexMetaData.getIndex());
-                        electedIndexMetaData = IndexMetaData.builder(electedIndexMetaData).state(IndexMetaData.State.CLOSE).build();
-                    }
-
-                    metaDataBuilder.put(electedIndexMetaData, false);
+        // verify index metadata
+        MetaData.Builder metaDataBuilder = MetaData.builder(electedGlobalState);
+        for (IndexMetaData indexMetaData : electedGlobalState) {
+            try {
+                if (indexMetaData.getState() == IndexMetaData.State.OPEN) {
+                    // verify that we can actually create this index - if not we recover it as closed with lots of warn logs
+                    indicesService.verifyIndexMetadata(nodeServicesProvider, indexMetaData);
                 }
+            } catch (Exception e) {
+                logger.warn("recovering index {} failed - recovering as closed", e, indexMetaData.getIndex());
+                indexMetaData = IndexMetaData.builder(indexMetaData).state(IndexMetaData.State.CLOSE).build();
+                metaDataBuilder.put(indexMetaData, true);
             }
         }
         ClusterState.Builder builder = ClusterState.builder(clusterService.state().getClusterName());
         builder.metaData(metaDataBuilder);
         listener.onSuccess(builder.build());
     }
+
     public void reset() throws Exception {
         try {
             Path[] dataPaths = nodeEnv.nodeDataPaths();
-            logger.trace("removing node data paths: [{}]", (Object)dataPaths);
+            logger.trace("removing node data paths: [{}]", (Object) dataPaths);
             IOUtils.rm(dataPaths);
         } catch (Exception ex) {
             logger.debug("failed to delete shard locations", ex);