[GitHub] [iceberg] rdblue commented on a change in pull request #1264: Expire snapshots action

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

rdblue commented on a change in pull request #1264:
URL: https://github.com/apache/iceberg/pull/1264#discussion_r467335599



##########
File path: spark/src/main/java/org/apache/iceberg/actions/ExpireSnapshotsAction.java
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@@ -0,0 +1,178 @@
+/*
+ * 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.actions;
+
+import java.util.Iterator;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.atomic.AtomicLong;
+import java.util.function.Consumer;
+import org.apache.iceberg.ExpireSnapshots;
+import org.apache.iceberg.HasTableOperations;
+import org.apache.iceberg.Table;
+import org.apache.iceberg.TableOperations;
+import org.apache.iceberg.exceptions.NotFoundException;
+import org.apache.iceberg.relocated.com.google.common.util.concurrent.MoreExecutors;
+import org.apache.iceberg.util.Tasks;
+import org.apache.spark.sql.Column;
+import org.apache.spark.sql.Dataset;
+import org.apache.spark.sql.Row;
+import org.apache.spark.sql.SparkSession;
+import org.apache.spark.sql.functions;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+public class ExpireSnapshotsAction extends BaseAction<ExpireSnapshotsActionResult> {
+  private static final Logger LOG = LoggerFactory.getLogger(ExpireSnapshotsAction.class);
+
+  private static final String DATA_FILE = "Data File";
+  private static final String MANIFEST = "Manifest";
+  private static final String MANIFEST_LIST = "Manifest List";
+
+  // Creates an executor service that runs each task in the thread that invokes execute/submit.
+  private static final ExecutorService DEFAULT_DELETE_EXECUTOR_SERVICE = MoreExecutors.newDirectExecutorService();
+
+  private final SparkSession spark;
+  private final Table table;
+  private final TableOperations ops;
+  private final Consumer<String> defaultDelete = new Consumer<String>() {
+    @Override
+    public void accept(String file) {
+      ops.io().deleteFile(file);
+    }
+  };
+
+  private Long expireSnapshotIdValue = null;
+  private Long expireOlderThanValue = null;
+  private Integer retainLastValue = null;
+  private Consumer<String> deleteFunc = defaultDelete;
+  private ExecutorService deleteExecutorService = DEFAULT_DELETE_EXECUTOR_SERVICE;
+
+  ExpireSnapshotsAction(SparkSession spark, Table table) {
+    this.spark = spark;
+    this.table = table;
+    this.ops = ((HasTableOperations) table).operations();
+  }
+
+  @Override
+  protected Table table() {
+    return table;
+  }
+
+  /**
+   * An executor service used when deleting files. Only used during the local delete phase of this Spark action
+   * @param executorService the service to use
+   * @return this for method chaining
+   */
+  public ExpireSnapshotsAction executeDeleteWith(ExecutorService executorService) {
+    this.deleteExecutorService = executorService;
+    return this;
+  }
+
+  public ExpireSnapshotsAction expireSnapshotId(long expireSnapshotId) {
+    this.expireSnapshotIdValue = expireSnapshotId;
+    return this;
+  }
+
+  public ExpireSnapshotsAction expireOlderThan(long timestampMillis) {
+    this.expireOlderThanValue = timestampMillis;
+    return this;
+  }
+
+  public ExpireSnapshotsAction retainLast(int numSnapshots) {
+    this.retainLastValue = numSnapshots;
+    return this;
+  }
+
+  public ExpireSnapshotsAction deleteWith(Consumer<String> newDeleteFunc) {
+    this.deleteFunc = newDeleteFunc;
+    return this;
+  }
+
+  @Override
+  public ExpireSnapshotsActionResult execute() {
+    //Metadata before Expiration
+    Dataset<Row> originalFiles = buildValidFileDF().persist();
+    originalFiles.count(); // Action to trigger persist
+
+    //Perform Expiration
+    ExpireSnapshots expireSnaps = table.expireSnapshots().cleanExpiredFiles(false);
+    if (expireSnapshotIdValue != null) {
+      expireSnaps = expireSnaps.expireSnapshotId(expireSnapshotIdValue);
+    }
+    if (expireOlderThanValue != null) {
+      expireSnaps = expireSnaps.expireOlderThan(expireOlderThanValue);
+    }
+    if (retainLastValue != null) {
+      expireSnaps = expireSnaps.retainLast(retainLastValue);
+    }
+    expireSnaps.commit();
+
+    // Metadata after Expiration
+    Dataset<Row> validFiles = buildValidFileDF();
+    Dataset<Row> filesToDelete = originalFiles.except(validFiles);
+
+    ExpireSnapshotsActionResult result =  deleteFiles(filesToDelete.toLocalIterator());
+    originalFiles.unpersist();
+    return result;
+  }
+
+  private Dataset<Row> appendTypeString(Dataset<Row> ds, String type) {
+    return ds.select(new Column("file_path"), functions.lit(type).as("file_type"));
+  }
+
+  private Dataset<Row> buildValidFileDF() {
+    return appendTypeString(buildValidDataFileDF(spark), DATA_FILE)
+        .union(appendTypeString(buildManifestFileDF(spark), MANIFEST))
+        .union(appendTypeString(buildManifestListDF(spark, table), MANIFEST_LIST));
+  }
+
+  private ExpireSnapshotsActionResult deleteFiles(Iterator<Row> paths) {
+    AtomicLong dataFileCount = new AtomicLong(0L);
+    AtomicLong manifestCount = new AtomicLong(0L);
+    AtomicLong manifestListCount = new AtomicLong(0L);
+
+    Tasks.foreach(paths)
+        .retry(3).stopRetryOn(NotFoundException.class).suppressFailureWhenFinished()
+        .executeWith(deleteExecutorService)
+        .onFailure((fileInfo, exc) ->
+            LOG.warn("Delete failed for {}: {}", fileInfo.getString(1), fileInfo.getString(0), exc))
+        .run(fileInfo -> {
+          String file = fileInfo.getString(0);
+          String type = fileInfo.getString(1);
+          deleteFunc.accept(file);
+          switch (type) {
+            case DATA_FILE:
+              dataFileCount.incrementAndGet();
+              LOG.trace("Deleted Data File: {}", file);
+              break;
+            case MANIFEST:
+              manifestCount.incrementAndGet();
+              LOG.warn("Deleted Manifest: {}", file);
+              break;
+            case MANIFEST_LIST:
+              manifestListCount.incrementAndGet();
+              LOG.warn("Deleted Manifest List: {}", file);
+              break;
+          }
+        });
+    LOG.warn("Deleted {} total files", dataFileCount.get() + manifestCount.get() + manifestListCount.get());

Review comment:
       I think it should be info. You're right that it isn't a warning because nothing went wrong. I would also say it isn't debug, because this is an important part of being able to monitor what happened. We don't need to know which files were deleted, but knowing how many were is a good thing to monitor. For example, if a user reports missing data, we'd go look at the logs for the last expiration and see whether this count is crazy high, indicating that we deleted too many files somehow.




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