HBASE-29088 The denominator cannot be 0 when calculating percentages in SnapshotStats

hbase-server/src/main/java/org/apache/hadoop/hbase/snapshot/SnapshotInfo.java

@@ -253,12 +253,16 @@ public long getNonSharedArchivedStoreFilesSize() {
 
     /** Returns the percentage of the shared store files */
     public float getSharedStoreFilePercentage() {
-      return ((float) hfilesSize.get() / (getStoreFilesSize())) * 100;
+      return getStoreFilesSize() == 0
+        ? 0
+        : ((float) hfilesSize.get() / (getStoreFilesSize())) * 100;
     }
 
     /** Returns the percentage of the mob store files */
     public float getMobStoreFilePercentage() {
-      return ((float) hfilesMobSize.get() / (getStoreFilesSize())) * 100;
+      return getStoreFilesSize() == 0
+        ? 0
+        : ((float) hfilesMobSize.get() / (getStoreFilesSize())) * 100;
     }
 
     /** Returns the total log size */

hbase-server/src/test/java/org/apache/hadoop/hbase/master/snapshot/TestSnapshotStats.java

@@ -0,0 +1,126 @@
+/*
+ * 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.hadoop.hbase.master.snapshot;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertTrue;
+
+import java.io.IOException;
+import java.util.Optional;
+import org.apache.hadoop.hbase.HBaseClassTestRule;
+import org.apache.hadoop.hbase.HBaseTestingUtil;
+import org.apache.hadoop.hbase.TableName;
+import org.apache.hadoop.hbase.client.Admin;
+import org.apache.hadoop.hbase.client.ColumnFamilyDescriptor;
+import org.apache.hadoop.hbase.client.ColumnFamilyDescriptorBuilder;
+import org.apache.hadoop.hbase.client.SnapshotDescription;
+import org.apache.hadoop.hbase.client.TableDescriptorBuilder;
+import org.apache.hadoop.hbase.snapshot.SnapshotInfo;
+import org.apache.hadoop.hbase.testclassification.LargeTests;
+import org.apache.hadoop.hbase.testclassification.MasterTests;
+import org.apache.hadoop.hbase.util.Bytes;
+import org.junit.After;
+import org.junit.Before;
+import org.junit.ClassRule;
+import org.junit.Rule;
+import org.junit.Test;
+import org.junit.experimental.categories.Category;
+import org.junit.rules.TestName;
+
+@Category({ MasterTests.class, LargeTests.class })
+public class TestSnapshotStats {
+  @ClassRule
+  public static final HBaseClassTestRule CLASS_RULE =
+    HBaseClassTestRule.forClass(TestSnapshotStats.class);
+
+  private final HBaseTestingUtil TEST_UTIL = new HBaseTestingUtil();
+  private Admin admin;
+
+  @Rule
+  public TestName name = new TestName();
+
+  @Before
+  public void setup() throws Exception {
+    TEST_UTIL.startMiniCluster(1);
+    admin = TEST_UTIL.getAdmin();
+  }
+
+  @After
+  public void tearDown() throws IOException {
+    admin.close();
+    TEST_UTIL.shutdownMiniCluster();
+    TEST_UTIL.getTestFileSystem().delete(TEST_UTIL.getDataTestDir(), true);
+  }
+
+  @Test
+  public void testSnapshotTableWithoutAnyData() throws IOException {
+    // Create a table without any data
+    TableName tableName = TableName.valueOf(name.getMethodName());
+    TableDescriptorBuilder tableDescriptorBuilder = TableDescriptorBuilder.newBuilder(tableName);
+    ColumnFamilyDescriptor columnFamilyDescriptor =
+      ColumnFamilyDescriptorBuilder.newBuilder(Bytes.toBytes("info")).build();
+    tableDescriptorBuilder.setColumnFamily(columnFamilyDescriptor);
+    admin.createTable(tableDescriptorBuilder.build());
+    assertTrue(admin.tableExists(tableName));
+
+    String snapshotName = "snapshot_" + name.getMethodName();
+    admin.snapshot(snapshotName, tableName);
+
+    Optional<SnapshotDescription> optional =
+      admin.listSnapshots().stream().filter(s -> snapshotName.equals(s.getName())).findFirst();
+    SnapshotDescription snapshotDescription = optional.orElseThrow();
+
+    SnapshotInfo.SnapshotStats snapshotStats =
+      SnapshotInfo.getSnapshotStats(TEST_UTIL.getConfiguration(), snapshotDescription);
+    assertEquals(0L, snapshotStats.getStoreFilesSize());
+    assertEquals(0, snapshotStats.getSharedStoreFilePercentage(), 0);
+
+    admin.deleteSnapshot(snapshotName);
+    admin.disableTable(tableName);
+    admin.deleteTable(tableName);
+  }
+
+  @Test
+  public void testSnapshotMobTableWithoutAnyData() throws IOException {
+    // Create a MOB table without any data
+    TableName tableName = TableName.valueOf(name.getMethodName());
+    TableDescriptorBuilder tableDescriptorBuilder = TableDescriptorBuilder.newBuilder(tableName);
+    ColumnFamilyDescriptor columnFamilyDescriptor =
+      ColumnFamilyDescriptorBuilder.newBuilder(Bytes.toBytes("info")).setMobEnabled(true).build();
+    tableDescriptorBuilder.setColumnFamily(columnFamilyDescriptor);
+    admin.createTable(tableDescriptorBuilder.build());
+    assertTrue(admin.tableExists(tableName));
+
+    String snapshotName = "snapshot_" + name.getMethodName();
+    admin.snapshot(snapshotName, tableName);
+
+    Optional<SnapshotDescription> optional =
+      admin.listSnapshots().stream().filter(s -> snapshotName.equals(s.getName())).findFirst();
+    SnapshotDescription snapshotDescription = optional.orElseThrow();
+
+    SnapshotInfo.SnapshotStats snapshotStats =
+      SnapshotInfo.getSnapshotStats(TEST_UTIL.getConfiguration(), snapshotDescription);
+    assertEquals(0L, snapshotStats.getStoreFilesSize());
+    assertEquals(0, snapshotStats.getSharedStoreFilePercentage(), 0);
+    assertEquals(0, snapshotStats.getMobStoreFilePercentage(), 0);
+
+    admin.deleteSnapshot(snapshotName);
+    admin.disableTable(tableName);
+    admin.deleteTable(tableName);
+  }
+}