[GitHub] [incubator-iceberg] danielcweeks commented on a change in pull request #200: Add SnapshotProducer that can rewrite manifests

[GitBox <gi...@apache.org>]

danielcweeks commented on a change in pull request #200: Add SnapshotProducer that can rewrite manifests
URL: https://github.com/apache/incubator-iceberg/pull/200#discussion_r290924942
 
 

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 File path: core/src/main/java/org/apache/iceberg/ReplaceManifests.java
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+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+package org.apache.iceberg;
+
+import com.google.common.base.Preconditions;
+import com.google.common.collect.Lists;
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.Set;
+import java.util.concurrent.atomic.AtomicInteger;
+import java.util.function.Function;
+import java.util.stream.Collectors;
+import org.apache.iceberg.exceptions.RuntimeIOException;
+import org.apache.iceberg.util.Tasks;
+import org.apache.iceberg.util.ThreadPools;
+
+import static org.apache.iceberg.TableProperties.MANIFEST_TARGET_SIZE_BYTES;
+import static org.apache.iceberg.TableProperties.MANIFEST_TARGET_SIZE_BYTES_DEFAULT;
+
+
+public class ReplaceManifests extends SnapshotProducer<RewriteManifests> implements RewriteManifests {
+  private final TableOperations ops;
+  private final PartitionSpec spec;
+  private final long manifestTargetSizeBytes;
+  private final SnapshotSummary.Builder summaryBuilder = SnapshotSummary.builder();
+  private final List<ManifestFile> newManifests = Collections.synchronizedList(Lists.newArrayList());
+  private final Map<Object, WriterWrapper> writers = Collections.synchronizedMap(new HashMap<>());
+  private final AtomicInteger manifestCount = new AtomicInteger(0);
+
+  private Function<DataFile, Object> clusterByFunc;
+  private Function<ManifestFile, Boolean> filterFunc;
+
+  ReplaceManifests(TableOperations ops) {
+    super(ops);
+    this.ops = ops;
+    this.spec = ops.current().spec();
+    this.manifestTargetSizeBytes =
+      ops.current().propertyAsLong(MANIFEST_TARGET_SIZE_BYTES, MANIFEST_TARGET_SIZE_BYTES_DEFAULT);
+  }
+
+  @Override
+  protected String operation() {
+    return DataOperations.REPLACE;
+  }
+
+  @Override
+  public RewriteManifests set(String property, String value) {
+    summaryBuilder.set(property, value);
+    return this;
+  }
+
+  @Override
+  protected Map<String, String> summary() {
+    return summaryBuilder.build();
+  }
+
+  @Override
+  public ReplaceManifests clusterBy(Function<DataFile, Object> func) {
+    this.clusterByFunc = func;
+    return this;
+  }
+
+  @Override
+  public ReplaceManifests filter(Function<ManifestFile, Boolean> func) {
+    this.filterFunc = func;
+    return this;
+  }
+
+  @Override
+  public List<ManifestFile> apply(TableMetadata base) {
+    Preconditions.checkNotNull(clusterByFunc, "clusterBy function cannot be null");
+
+    List<ManifestFile> existingManifests = Collections.synchronizedList(new ArrayList<>());
+
+    try {
+      Tasks.foreach(base.currentSnapshot().manifests())
+          .executeWith(ThreadPools.getWorkerPool())
+          .run(manifest -> {
+            if (filterFunc != null && !filterFunc.apply(manifest)) {
+              existingManifests.add(manifest);
+            } else {
+              long entryNum = manifest.addedFilesCount() + manifest.existingFilesCount() + manifest.deletedFilesCount();
+              long avgEntryLen = manifest.length() / entryNum;
+
+              try (ManifestReader reader =
+                     ManifestReader.read(ops.io().newInputFile(manifest.path()))) {
+                FilteredManifest filteredManifest = reader.select(Lists.newArrayList("*"));
+                filteredManifest.iterator().forEachRemaining(
+                    file -> appendFile(file, avgEntryLen, clusterByFunc.apply(file))
+                );
+
+              } catch (IOException x) {
+                throw new RuntimeIOException(x);
+              }
+            }
+          });
+    } finally {
+      Tasks.foreach(writers.values()).executeWith(ThreadPools.getWorkerPool()).run(writer -> writer.close());
+    }
+
+    newManifests.addAll(
+        writers.values()
+          .stream()
+          .map(WriterWrapper::toManifestFile)
+          .collect(Collectors.toList())
+    );
+
+    // put new manifests at the beginning
+    List<ManifestFile> apply = new ArrayList<>();
+    apply.addAll(newManifests);
+    apply.addAll(existingManifests);
+
+    return apply;
+  }
+
+  private void appendFile(DataFile file, long avgEntryLen, Object key) {
+    Preconditions.checkNotNull(file, "Data file cannot be null");
+    Preconditions.checkNotNull(key, "Key cannot be null");
+
+    synchronized (summaryBuilder) {
+      summaryBuilder.addedFile(spec, file);
 
 Review comment:
   @bryanck Looks like this is potentially pulling all the partitions into memory during this process.  While this may work for smaller cases, I doubt this will scale given the current summary builder.  We could not write these at all since this is a replace operation and the partition summaries won't be used for any current use case.  I assume we would fallback elsewhere if the summaries don't exist.

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