From 2e111a179b5e51071d40923a422df54cc82fabf4 Mon Sep 17 00:00:00 2001
From: Walaa Eldin Moustafa <wmoustafa@linkedin.com>
Date: Thu, 26 Nov 2020 17:13:08 -0800
Subject: [PATCH] Hive Metadata Scan: Do not throw an exception on dangling
 partitions; log warning message (#50)

---
 .../iceberg/hive/legacy/FileSystemUtils.java  | 10 +++++++++
 .../legacy/LegacyHiveTableOperations.java     | 16 +++++++++++---
 .../hive/legacy/TestLegacyHiveTableScan.java  | 22 +++++++++++++++++++
 3 files changed, 45 insertions(+), 3 deletions(-)

diff --git a/hive-metastore/src/main/java/org/apache/iceberg/hive/legacy/FileSystemUtils.java b/hive-metastore/src/main/java/org/apache/iceberg/hive/legacy/FileSystemUtils.java
index 81cad5f5b..6c223143f 100644
--- a/hive-metastore/src/main/java/org/apache/iceberg/hive/legacy/FileSystemUtils.java
+++ b/hive-metastore/src/main/java/org/apache/iceberg/hive/legacy/FileSystemUtils.java
@@ -50,6 +50,16 @@ static List<FileStatus> listFiles(String directory, Configuration conf) {
     return Arrays.asList(files);
   }
 
+  static boolean exists(String file, Configuration conf) {
+    final Path filePath = new Path(file);
+    try {
+      FileSystem fs = filePath.getFileSystem(conf);
+      return fs.exists(filePath);
+    } catch (IOException e) {
+      throw new RuntimeIOException(e, "Error determining if file or directory exists: " + file);
+    }
+  }
+
   private enum HiddenPathFilter implements PathFilter {
     INSTANCE;
 
diff --git a/hive-metastore/src/main/java/org/apache/iceberg/hive/legacy/LegacyHiveTableOperations.java b/hive-metastore/src/main/java/org/apache/iceberg/hive/legacy/LegacyHiveTableOperations.java
index c7507acf7..c55e486f5 100644
--- a/hive-metastore/src/main/java/org/apache/iceberg/hive/legacy/LegacyHiveTableOperations.java
+++ b/hive-metastore/src/main/java/org/apache/iceberg/hive/legacy/LegacyHiveTableOperations.java
@@ -114,9 +114,19 @@ Iterable<Iterable<DataFile>> getFilesByFilter(Expression expression) {
 
     Iterable<Iterable<DataFile>> filesPerDirectory = Iterables.transform(
         matchingDirectories,
-        directory -> Iterables.transform(
-            FileSystemUtils.listFiles(directory.location(), conf),
-            file -> createDataFile(file, current().spec(), directory.partitionData(), directory.format())));
+        directory -> {
+          List<FileStatus> files;
+          if (FileSystemUtils.exists(directory.location(), conf)) {
+            files = FileSystemUtils.listFiles(directory.location(), conf);
+          } else {
+            LOG.warn("Cannot find directory: {}. Skipping.", directory.location());
+            files = ImmutableList.of();
+          }
+          return Iterables.transform(
+              files,
+              file -> createDataFile(file, current().spec(), directory.partitionData(), directory.format())
+          );
+        });
 
     // Note that we return an Iterable of Iterables here so that the TableScan can process iterables of individual
     // directories in parallel hence resulting in a parallel file listing
diff --git a/hive-metastore/src/test/java/org/apache/iceberg/hive/legacy/TestLegacyHiveTableScan.java b/hive-metastore/src/test/java/org/apache/iceberg/hive/legacy/TestLegacyHiveTableScan.java
index dc060d0ee..55667089a 100644
--- a/hive-metastore/src/test/java/org/apache/iceberg/hive/legacy/TestLegacyHiveTableScan.java
+++ b/hive-metastore/src/test/java/org/apache/iceberg/hive/legacy/TestLegacyHiveTableScan.java
@@ -19,6 +19,7 @@
 
 package org.apache.iceberg.hive.legacy;
 
+import java.io.File;
 import java.io.IOException;
 import java.net.URI;
 import java.nio.file.Files;
@@ -29,6 +30,7 @@
 import java.util.Map;
 import java.util.stream.Collectors;
 import java.util.stream.StreamSupport;
+import org.apache.commons.io.FileUtils;
 import org.apache.hadoop.hive.metastore.TableType;
 import org.apache.hadoop.hive.metastore.api.FieldSchema;
 import org.apache.hadoop.hive.metastore.api.Partition;
@@ -107,6 +109,17 @@ public void testHiveScanMultiPartition() throws Exception {
     filesMatch(ImmutableMap.of("pcol=ds/pIntCol=2/B", AVRO, "pcol=ds/pIntCol=1/A", AVRO), hiveScan(table));
   }
 
+  @Test
+  public void testHiveScanDanglingPartitions() throws Exception {
+    String tableName = "dangling_partition";
+    Table table = createTable(tableName, DATA_COLUMNS, PARTITION_COLUMNS);
+    addPartition(table, ImmutableList.of("ds", 1), AVRO, "A");
+    addPartition(table, ImmutableList.of("ds", 2), AVRO, "B");
+    addPartition(table, ImmutableList.of("ds", 3), AVRO, "C");
+    makePartitionDangling(table, ImmutableList.of("ds", 3));
+    filesMatch(ImmutableMap.of("pcol=ds/pIntCol=2/B", AVRO, "pcol=ds/pIntCol=1/A", AVRO), hiveScan(table));
+  }
+
   @Test
   public void testHiveScanNoAvroSchema() throws Exception {
     String tableName = "hive_scan_no_avro_schema";
@@ -256,6 +269,15 @@ private void addPartition(Table table, List<Object> partitionValues, FileFormat
     }
   }
 
+  private void makePartitionDangling(Table table, List<Object> partitionValues) throws Exception {
+    String partitionLocation = metastoreClient.getPartition(
+        table.getDbName(),
+        table.getTableName(),
+        Lists.transform(partitionValues, Object::toString)
+    ).getSd().getLocation();
+    FileUtils.deleteDirectory(new File(new URI(partitionLocation)));
+  }
+
   private Map<String, FileFormat> hiveScan(Table table) {
     return hiveScan(table, Expressions.alwaysTrue());
   }