Share serialized settings and mappings between partition definitions (elastic#1477)

In situations where large pushdown queries, large mappings, and indices with 
many shards are combined, we can inflate the driver program memory very 
quickly as we duplicate the settings and mappings data for each 
ParititionDefinition we create. This change serializes the settings and mapping 
data once and shares the immutable state between all PartitionDefinition 
instances to avoid ballooning memory.

Author: jbaiera

mr/src/main/java/org/elasticsearch/hadoop/rest/PartitionDefinition.java

@@ -42,16 +42,33 @@ public class PartitionDefinition implements Serializable, Comparable<PartitionDe
     private final String serializedSettings, serializedMapping;
     private final String[] locations;
 
-    public PartitionDefinition(Settings settings, Mapping mapping, String index, int shardId) {
-        this(settings, mapping, index, shardId, null, EMPTY_ARRAY);
-    }
+    public static class PartitionDefinitionBuilder {
+        private final String serializedSettings, serializedMapping;
+
+        private PartitionDefinitionBuilder(Settings settings, Mapping resolvedMapping) {
+            this.serializedSettings = settings == null ? null : settings.save();
+            this.serializedMapping = resolvedMapping == null ? null : IOUtils.serializeToBase64(resolvedMapping);
+        }
+
+        public PartitionDefinition build(String index, int shardId) {
+            return new PartitionDefinition(serializedSettings, serializedMapping, index, shardId, null, EMPTY_ARRAY);
+        }
+
+        public PartitionDefinition build(String index, int shardId, String[] locations) {
+            return new PartitionDefinition(serializedSettings, serializedMapping, index, shardId, null, locations);
+        }
+
+        public PartitionDefinition build(String index, int shardId, Slice slice) {
+            return new PartitionDefinition(serializedSettings, serializedMapping, index, shardId, slice, EMPTY_ARRAY);
+        }
 
-    public PartitionDefinition(Settings settings, Mapping mapping, String index, int shardId, String[] locations) {
-        this(settings, mapping, index, shardId, null, locations);
+        public PartitionDefinition build(String index, int shardId, Slice slice, String[] locations) {
+            return new PartitionDefinition(serializedSettings, serializedMapping, index, shardId, slice, locations);
+        }
     }
 
-    public PartitionDefinition(Settings settings, Mapping mapping, String index, int shardId, Slice slice) {
-        this(settings, mapping, index, shardId, slice, EMPTY_ARRAY);
+    public static PartitionDefinitionBuilder builder(Settings settings, Mapping resolvedMapping) {
+        return new PartitionDefinitionBuilder(settings, resolvedMapping);
     }
 
     /**
@@ -63,19 +80,11 @@ public PartitionDefinition(Settings settings, Mapping mapping, String index, int
      * @param slice The slice the partition will be executed on or null
      * @param locations The locations where to find nodes (hostname:port or ip:port) that can execute the partition locally
      */
-    public PartitionDefinition(Settings settings, Mapping mapping, String index, int shardId, Slice slice, String[] locations) {
+    private PartitionDefinition(String serializedSettings, String serializedMapping, String index, int shardId, Slice slice, String[] locations) {
         this.index = index;
         this.shardId = shardId;
-        if (settings != null) {
-            this.serializedSettings = settings.save();
-        } else {
-            this.serializedSettings = null;
-        }
-        if (mapping != null) {
-            this.serializedMapping = IOUtils.serializeToBase64(mapping);
-        } else {
-            this.serializedMapping = null;
-        }
+        this.serializedSettings = serializedSettings;
+        this.serializedMapping = serializedMapping;
         this.slice = slice;
         this.locations = locations;
     }

mr/src/main/java/org/elasticsearch/hadoop/rest/RestService.java

@@ -285,6 +285,7 @@ static List<PartitionDefinition> findShardPartitions(Settings settings, MappingS
                                                          List<List<Map<String, Object>>> shards, Log log) {
         Mapping resolvedMapping = mappingSet == null ? null : mappingSet.getResolvedView();
         List<PartitionDefinition> partitions = new ArrayList<PartitionDefinition>(shards.size());
+        PartitionDefinition.PartitionDefinitionBuilder partitionBuilder = PartitionDefinition.builder(settings, resolvedMapping);
         for (List<Map<String, Object>> group : shards) {
             String index = null;
             int shardId = -1;
@@ -308,8 +309,7 @@ static List<PartitionDefinition> findShardPartitions(Settings settings, MappingS
                             "Check your cluster status to see if it is unstable!");
                 }
             } else {
-                PartitionDefinition partition = new PartitionDefinition(settings, resolvedMapping, index, shardId,
-                        locationList.toArray(new String[0]));
+                PartitionDefinition partition = partitionBuilder.build(index, shardId, locationList.toArray(new String[0]));
                 partitions.add(partition);
             }
         }
@@ -326,6 +326,7 @@ static List<PartitionDefinition> findSlicePartitions(RestClient client, Settings
         Assert.notNull(maxDocsPerPartition, "Attempting to find slice partitions but maximum documents per partition is not set.");
         Resource readResource = new Resource(settings, true);
         Mapping resolvedMapping = mappingSet == null ? null : mappingSet.getResolvedView();
+        PartitionDefinition.PartitionDefinitionBuilder partitionBuilder = PartitionDefinition.builder(settings, resolvedMapping);
 
         List<PartitionDefinition> partitions = new ArrayList<PartitionDefinition>(shards.size());
         for (List<Map<String, Object>> group : shards) {
@@ -362,7 +363,7 @@ static List<PartitionDefinition> findSlicePartitions(RestClient client, Settings
                 int numPartitions = (int) Math.max(1, numDocs / maxDocsPerPartition);
                 for (int i = 0; i < numPartitions; i++) {
                     PartitionDefinition.Slice slice = new PartitionDefinition.Slice(i, numPartitions);
-                    partitions.add(new PartitionDefinition(settings, resolvedMapping, index, shardId, slice, locations));
+                    partitions.add(partitionBuilder.build(index, shardId, slice, locations));
                 }
             }
         }

mr/src/test/java/org/elasticsearch/hadoop/rest/FindPartitionsTest.java

@@ -51,16 +51,17 @@ public class FindPartitionsTest {
 
     private static final PartitionDefinition[] EXPECTED_SHARDS_PARTITIONS;
     static {
+        PartitionDefinition.PartitionDefinitionBuilder partitionBuilder = PartitionDefinition.builder(null, null);
         List<PartitionDefinition> expected =
                 new ArrayList<PartitionDefinition>();
         for (int i = 0; i < 15; i++) {
-            expected.add(new PartitionDefinition(null, null, "index1", i));
+            expected.add(partitionBuilder.build("index1", i));
         }
         for (int i = 0; i < 18; i++) {
-            expected.add(new PartitionDefinition(null, null, "index2", i));
+            expected.add(partitionBuilder.build("index2", i));
         }
         for (int i = 0; i < 1; i++) {
-            expected.add(new PartitionDefinition(null, null, "index3", i));
+            expected.add(partitionBuilder.build("index3", i));
         }
         Collections.sort(expected);
         EXPECTED_SHARDS_PARTITIONS = expected.toArray(new PartitionDefinition[0]);

mr/src/test/java/org/elasticsearch/hadoop/rest/PartitionDefinitionTest.java

@@ -21,6 +21,7 @@
 import org.codehaus.jackson.JsonParser;
 import org.codehaus.jackson.map.ObjectMapper;
 import org.elasticsearch.hadoop.cfg.PropertiesSettings;
+import org.elasticsearch.hadoop.rest.PartitionDefinition.PartitionDefinitionBuilder;
 import org.elasticsearch.hadoop.serialization.dto.mapping.FieldParser;
 import org.elasticsearch.hadoop.serialization.dto.mapping.Mapping;
 import org.elasticsearch.hadoop.util.BytesArray;
@@ -35,8 +36,7 @@
 import java.io.ObjectOutputStream;
 import java.util.Map;
 
-import static org.junit.Assert.assertArrayEquals;
-import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.*;
 
 public class PartitionDefinitionTest {
 
@@ -55,7 +55,7 @@ public void testWritable() throws IOException {
         PropertiesSettings settings = new PropertiesSettings();
         settings.setProperty("setting1", "value1");
         settings.setProperty("setting2", "value2");
-        PartitionDefinition expected = new PartitionDefinition(settings, mapping, "foo", 12,
+        PartitionDefinition expected = PartitionDefinition.builder(settings, mapping).build("foo", 12,
                 new String[] {"localhost:9200", "otherhost:9200"});
         BytesArray bytes = writeWritablePartition(expected);
         PartitionDefinition def = readWritablePartition(bytes);
@@ -68,7 +68,7 @@ public void testSerializable() throws IOException, ClassNotFoundException {
         PropertiesSettings settings = new PropertiesSettings();
         settings.setProperty("setting1", "value1");
         settings.setProperty("setting2", "value2");
-        PartitionDefinition expected = new PartitionDefinition(settings, mapping, "bar", 37,
+        PartitionDefinition expected = PartitionDefinition.builder(settings, mapping).build("bar", 37,
                 new String[] {"localhost:9200", "otherhost:9200"});
         BytesArray bytes = writeSerializablePartition(expected);
         PartitionDefinition def = readSerializablePartition(bytes);
@@ -81,7 +81,7 @@ public void testWritableWithSlice() throws IOException {
         PropertiesSettings settings = new PropertiesSettings();
         settings.setProperty("setting1", "value1");
         settings.setProperty("setting2", "value2");
-        PartitionDefinition expected = new PartitionDefinition(settings, mapping, "foo", 12, new PartitionDefinition.Slice(10, 27),
+        PartitionDefinition expected = PartitionDefinition.builder(settings, mapping).build("foo", 12, new PartitionDefinition.Slice(10, 27),
                 new String[] {"localhost:9200", "otherhost:9200"});
         BytesArray bytes = writeWritablePartition(expected);
         PartitionDefinition def = readWritablePartition(bytes);
@@ -95,13 +95,35 @@ public void testSerializableWithSlice() throws IOException, ClassNotFoundExcepti
         settings.setProperty("setting1", "value1");
         settings.setProperty("setting2", "value2");
 
-        PartitionDefinition expected = new PartitionDefinition(settings, mapping, "bar", 37,
+        PartitionDefinition expected = PartitionDefinition.builder(settings, mapping).build("bar", 37,
                 new PartitionDefinition.Slice(13, 35),  new String[] {"localhost:9200", "otherhost:9200"});
         BytesArray bytes = writeSerializablePartition(expected);
         PartitionDefinition def = readSerializablePartition(bytes);
         assertPartitionEquals(expected, def);
     }
 
+    @Test
+    public void testNonDuplicationOfConfiguration() throws IOException {
+        Mapping mapping = getTestMapping();
+        PropertiesSettings settings = new PropertiesSettings();
+        settings.setProperty("setting1", "value1");
+        settings.setProperty("setting2", "value2");
+        PartitionDefinitionBuilder partitionBuilder = PartitionDefinition.builder(settings, mapping);
+
+        PartitionDefinition first = partitionBuilder.build("foo", 11,
+                new String[] {"localhost:9200", "otherhost:9200"});
+        PartitionDefinition second = partitionBuilder.build("foo", 12,
+                new String[] {"localhost:9200", "otherhost:9200"});
+        assertNotEquals(first, second);
+        assertSame(first.getSerializedSettings(), second.getSerializedSettings());
+        assertSame(first.getSerializedMapping(), second.getSerializedMapping());
+        BytesArray bytes = writeWritablePartition(first);
+        PartitionDefinition def = readWritablePartition(bytes);
+        assertPartitionEquals(first, def);
+        assertNotSame(first.getSerializedSettings(), def.getSerializedSettings());
+        assertNotSame(first.getSerializedMapping(), def.getSerializedMapping());
+    }
+
     static PartitionDefinition readSerializablePartition(BytesArray bytes) throws IOException, ClassNotFoundException {
         FastByteArrayInputStream in = new FastByteArrayInputStream(bytes);
         ObjectInputStream ois = new ObjectInputStream(in);

mr/src/test/java/org/elasticsearch/hadoop/rest/RestServiceTest.java

@@ -75,12 +75,13 @@ public void setup() {
 
         ShardInfo sh6 = new ShardInfo(info);
 
-        pd1 = new PartitionDefinition(null, null, sh1.getIndex(), sh1.getName());
-        pd2 = new PartitionDefinition(null, null, sh2.getIndex(), sh2.getName());
-        pd3 = new PartitionDefinition(null, null, sh3.getIndex(), sh3.getName());
-        pd4 = new PartitionDefinition(null, null, sh4.getIndex(), sh4.getName());
-        pd5 = new PartitionDefinition(null, null, sh5.getIndex(), sh5.getName());
-        pd6 = new PartitionDefinition(null, null, sh6.getIndex(), sh6.getName());
+        PartitionDefinition.PartitionDefinitionBuilder bldr = PartitionDefinition.builder(null, null);
+        pd1 = bldr.build(sh1.getIndex(), sh1.getName());
+        pd2 = bldr.build(sh2.getIndex(), sh2.getName());
+        pd3 = bldr.build(sh3.getIndex(), sh3.getName());
+        pd4 = bldr.build(sh4.getIndex(), sh4.getName());
+        pd5 = bldr.build(sh5.getIndex(), sh5.getName());
+        pd6 = bldr.build(sh6.getIndex(), sh6.getName());
 
         pds = Arrays.asList(pd1, pd2, pd3, pd4, pd5, pd6);
     }