Adding best_compression (elastic#49974)

This commit adds a `codec` parameter to the ILM `forcemerge` action. When setting the codec to `best_compression` ILM will close the index, then update the codec setting, re-open the index, and finally perform a force merge.

Author: SivagurunathanV

x-pack/plugin/core/src/main/java/org/elasticsearch/xpack/core/ilm/CloseIndexStep.java

@@ -0,0 +1,50 @@
+/*
+ * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
+ * or more contributor license agreements. Licensed under the Elastic License;
+ * you may not use this file except in compliance with the Elastic License.
+ */
+
+package org.elasticsearch.xpack.core.ilm;
+
+import org.elasticsearch.ElasticsearchException;
+import org.elasticsearch.action.ActionListener;
+import org.elasticsearch.action.admin.indices.close.CloseIndexRequest;
+import org.elasticsearch.client.Client;
+import org.elasticsearch.cluster.ClusterState;
+import org.elasticsearch.cluster.ClusterStateObserver;
+import org.elasticsearch.cluster.metadata.IndexMetaData;
+
+/**
+ * Invokes a close step on a single index.
+ */
+
+public class CloseIndexStep extends AsyncActionStep {
+    public static final String NAME = "close-index";
+
+    CloseIndexStep(StepKey key, StepKey nextStepKey, Client client) {
+        super(key, nextStepKey, client);
+    }
+
+    @Override
+    public void performAction(IndexMetaData indexMetaData, ClusterState currentClusterState,
+                              ClusterStateObserver observer, Listener listener) {
+        if (indexMetaData.getState() == IndexMetaData.State.OPEN) {
+            CloseIndexRequest request = new CloseIndexRequest(indexMetaData.getIndex().getName());
+            getClient().admin().indices()
+                .close(request, ActionListener.wrap(closeIndexResponse -> {
+                    if (closeIndexResponse.isAcknowledged() == false) {
+                        throw new ElasticsearchException("close index request failed to be acknowledged");
+                    }
+                    listener.onResponse(true);
+                }, listener::onFailure));
+        }
+        else {
+            listener.onResponse(true);
+        }
+    }
+
+    @Override
+    public boolean isRetryable() {
+        return true;
+    }
+}

x-pack/plugin/core/src/main/java/org/elasticsearch/xpack/core/ilm/ForceMergeAction.java

@@ -5,8 +5,11 @@
  */
 package org.elasticsearch.xpack.core.ilm;
 
+import org.elasticsearch.Version;
 import org.elasticsearch.client.Client;
+import org.elasticsearch.cluster.health.ClusterHealthStatus;
 import org.elasticsearch.cluster.metadata.IndexMetaData;
+import org.elasticsearch.common.Nullable;
 import org.elasticsearch.common.ParseField;
 import org.elasticsearch.common.Strings;
 import org.elasticsearch.common.io.stream.StreamInput;
@@ -15,10 +18,12 @@
 import org.elasticsearch.common.xcontent.ConstructingObjectParser;
 import org.elasticsearch.common.xcontent.XContentBuilder;
 import org.elasticsearch.common.xcontent.XContentParser;
+import org.elasticsearch.index.codec.CodecService;
+import org.elasticsearch.index.engine.EngineConfig;
 import org.elasticsearch.xpack.core.ilm.Step.StepKey;
 
 import java.io.IOException;
-import java.util.Arrays;
+import java.util.ArrayList;
 import java.util.List;
 import java.util.Objects;
 
@@ -28,42 +33,62 @@
 public class ForceMergeAction implements LifecycleAction {
     public static final String NAME = "forcemerge";
     public static final ParseField MAX_NUM_SEGMENTS_FIELD = new ParseField("max_num_segments");
+    public static final ParseField CODEC = new ParseField("index_codec");
 
     private static final ConstructingObjectParser<ForceMergeAction, Void> PARSER = new ConstructingObjectParser<>(NAME,
         false, a -> {
         int maxNumSegments = (int) a[0];
-        return new ForceMergeAction(maxNumSegments);
+        String codec = a[1] != null ? (String) a[1] : null;
+        return new ForceMergeAction(maxNumSegments, codec);
     });
 
     static {
         PARSER.declareInt(ConstructingObjectParser.constructorArg(), MAX_NUM_SEGMENTS_FIELD);
+        PARSER.declareString(ConstructingObjectParser.optionalConstructorArg(), CODEC);
     }
 
     private final int maxNumSegments;
+    private final String codec;
 
     public static ForceMergeAction parse(XContentParser parser) {
         return PARSER.apply(parser, null);
     }
 
-    public ForceMergeAction(int maxNumSegments) {
+    public ForceMergeAction(int maxNumSegments, @Nullable String codec) {
         if (maxNumSegments <= 0) {
             throw new IllegalArgumentException("[" + MAX_NUM_SEGMENTS_FIELD.getPreferredName()
                 + "] must be a positive integer");
         }
         this.maxNumSegments = maxNumSegments;
+        if (codec != null && CodecService.BEST_COMPRESSION_CODEC.equals(codec) == false) {
+            throw new IllegalArgumentException("unknown index codec: [" + codec + "]");
+        }
+        this.codec = codec;
     }
 
     public ForceMergeAction(StreamInput in) throws IOException {
         this.maxNumSegments = in.readVInt();
+        if (in.getVersion().onOrAfter(Version.V_8_0_0)) {
+            this.codec = in.readOptionalString();
+        } else {
+            this.codec = null;
+        }
     }
 
     public int getMaxNumSegments() {
         return maxNumSegments;
     }
 
+    public String getCodec() {
+        return this.codec;
+    }
+
     @Override
     public void writeTo(StreamOutput out) throws IOException {
         out.writeVInt(maxNumSegments);
+        if (out.getVersion().onOrAfter(Version.V_8_0_0)) {
+            out.writeOptionalString(codec);
+        }
     }
 
     @Override
@@ -80,27 +105,58 @@ public boolean isSafeAction() {
     public XContentBuilder toXContent(XContentBuilder builder, Params params) throws IOException {
         builder.startObject();
         builder.field(MAX_NUM_SEGMENTS_FIELD.getPreferredName(), maxNumSegments);
+        if (codec != null) {
+            builder.field(CODEC.getPreferredName(), codec);
+        }
         builder.endObject();
         return builder;
     }
 
     @Override
     public List<Step> toSteps(Client client, String phase, Step.StepKey nextStepKey) {
         Settings readOnlySettings = Settings.builder().put(IndexMetaData.SETTING_BLOCKS_WRITE, true).build();
+        Settings bestCompressionSettings = Settings.builder()
+            .put(EngineConfig.INDEX_CODEC_SETTING.getKey(), CodecService.BEST_COMPRESSION_CODEC).build();
 
         StepKey readOnlyKey = new StepKey(phase, NAME, ReadOnlyAction.NAME);
         StepKey forceMergeKey = new StepKey(phase, NAME, ForceMergeStep.NAME);
         StepKey countKey = new StepKey(phase, NAME, SegmentCountStep.NAME);
 
+        StepKey closeKey = new StepKey(phase, NAME, CloseIndexStep.NAME);
+        StepKey openKey = new StepKey(phase, NAME, OpenIndexStep.NAME);
+        StepKey waitForGreenIndexKey = new StepKey(phase, NAME, WaitForIndexColorStep.NAME);
+        StepKey updateCompressionKey = new StepKey(phase, NAME, UpdateSettingsStep.NAME);
+
         UpdateSettingsStep readOnlyStep = new UpdateSettingsStep(readOnlyKey, forceMergeKey, client, readOnlySettings);
         ForceMergeStep forceMergeStep = new ForceMergeStep(forceMergeKey, countKey, client, maxNumSegments);
+        CloseIndexStep closeIndexStep = new CloseIndexStep(closeKey, updateCompressionKey, client);
+        ForceMergeStep forceMergeStepForBestCompression = new ForceMergeStep(forceMergeKey, closeKey, client, maxNumSegments);
+        UpdateSettingsStep updateBestCompressionSettings = new UpdateSettingsStep(updateCompressionKey,
+            openKey, client, bestCompressionSettings);
+        OpenIndexStep openIndexStep = new OpenIndexStep(openKey, waitForGreenIndexKey, client);
+        WaitForIndexColorStep waitForIndexGreenStep = new WaitForIndexColorStep(waitForGreenIndexKey,
+            forceMergeKey, ClusterHealthStatus.GREEN);
         SegmentCountStep segmentCountStep = new SegmentCountStep(countKey, nextStepKey, client, maxNumSegments);
-        return Arrays.asList(readOnlyStep, forceMergeStep, segmentCountStep);
+
+        List<Step> mergeSteps = new ArrayList<>();
+        mergeSteps.add(readOnlyStep);
+
+        if (codec != null && codec.equals(CodecService.BEST_COMPRESSION_CODEC)) {
+            mergeSteps.add(forceMergeStepForBestCompression);
+            mergeSteps.add(closeIndexStep);
+            mergeSteps.add(updateBestCompressionSettings);
+            mergeSteps.add(openIndexStep);
+            mergeSteps.add(waitForIndexGreenStep);
+        }
+
+        mergeSteps.add(forceMergeStep);
+        mergeSteps.add(segmentCountStep);
+        return mergeSteps;
     }
 
     @Override
     public int hashCode() {
-        return Objects.hash(maxNumSegments);
+        return Objects.hash(maxNumSegments, codec);
     }
 
     @Override
@@ -112,7 +168,8 @@ public boolean equals(Object obj) {
             return false;
         }
         ForceMergeAction other = (ForceMergeAction) obj;
-        return Objects.equals(maxNumSegments, other.maxNumSegments);
+        return Objects.equals(this.maxNumSegments, other.maxNumSegments)
+            && Objects.equals(this.codec, other.codec);
     }
 
     @Override

x-pack/plugin/core/src/main/java/org/elasticsearch/xpack/core/ilm/OpenIndexStep.java

@@ -0,0 +1,52 @@
+/*
+ * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
+ * or more contributor license agreements. Licensed under the Elastic License;
+ * you may not use this file except in compliance with the Elastic License.
+ */
+
+package org.elasticsearch.xpack.core.ilm;
+
+import org.elasticsearch.ElasticsearchException;
+import org.elasticsearch.action.ActionListener;
+import org.elasticsearch.action.admin.indices.open.OpenIndexRequest;
+import org.elasticsearch.client.Client;
+import org.elasticsearch.cluster.ClusterState;
+import org.elasticsearch.cluster.ClusterStateObserver;
+import org.elasticsearch.cluster.metadata.IndexMetaData;
+
+/**
+ * Invokes a open step on a single index.
+ */
+
+final class OpenIndexStep extends AsyncActionStep {
+
+    static final String NAME = "open-index";
+
+    OpenIndexStep(StepKey key, StepKey nextStepKey, Client client) {
+        super(key, nextStepKey, client);
+    }
+
+    @Override
+    public void performAction(IndexMetaData indexMetaData, ClusterState currentClusterState,
+                              ClusterStateObserver observer, Listener listener) {
+        if (indexMetaData.getState() == IndexMetaData.State.CLOSE) {
+            OpenIndexRequest request = new OpenIndexRequest(indexMetaData.getIndex().getName());
+            getClient().admin().indices()
+                .open(request,
+                    ActionListener.wrap(openIndexResponse -> {
+                        if (openIndexResponse.isAcknowledged() == false) {
+                            throw new ElasticsearchException("open index request failed to be acknowledged");
+                        }
+                        listener.onResponse(true);
+                    }, listener::onFailure));
+
+        } else {
+            listener.onResponse(true);
+        }
+    }
+
+    @Override
+    public boolean isRetryable() {
+        return true;
+    }
+}