HBASE-26615 Snapshot referenced data files are deleted when delete a table with merge regions (#3971)

Signed-off-by: Duo Zhang <zhangduo@apache.org>

hbase-server/src/main/java/org/apache/hadoop/hbase/master/procedure/DeleteTableProcedure.java

@@ -54,6 +54,7 @@ import org.apache.hadoop.hbase.shaded.protobuf.ProtobufUtil;
 import org.apache.hadoop.hbase.shaded.protobuf.generated.HBaseProtos;
 import org.apache.hadoop.hbase.shaded.protobuf.generated.MasterProcedureProtos;
 import org.apache.hadoop.hbase.shaded.protobuf.generated.MasterProcedureProtos.DeleteTableState;
+import org.apache.hbase.thirdparty.org.apache.commons.collections4.CollectionUtils;
 
 @InterfaceAudience.Private
 public class DeleteTableProcedure
@@ -281,9 +282,18 @@ public class DeleteTableProcedure
     if (fs.exists(tableDir)) {
       // Archive regions from FS (temp directory)
       if (archive) {
-        List<Path> regionDirList = regions.stream().filter(RegionReplicaUtil::isDefaultReplica)
+        List<Path> regionDirList = new ArrayList<>();
-          .map(region ->
+        for (RegionInfo region : regions) {
-            FSUtils.getRegionDirFromTableDir(tableDir, region)).collect(Collectors.toList());
+          if (RegionReplicaUtil.isDefaultReplica(region)) {
+            regionDirList.add(FSUtils.getRegionDirFromTableDir(tableDir, region));
+            List<RegionInfo> mergeRegions =
+                env.getAssignmentManager().getRegionStateStore().getMergeRegions(region);
+            if (!CollectionUtils.isEmpty(mergeRegions)) {
+              mergeRegions.stream().forEach(
+                r -> regionDirList.add(FSUtils.getRegionDirFromTableDir(tableDir, r)));
+            }
+          }
+        }
         HFileArchiver
           .archiveRegions(env.getMasterConfiguration(), fs, mfs.getRootDir(), tableDir,
             regionDirList);

hbase-server/src/test/java/org/apache/hadoop/hbase/client/TestTableSnapshotScanner.java

@@ -468,6 +468,48 @@ public class TestTableSnapshotScanner {
     }
   }
 
+  @Test
+  public void testDeleteTableWithMergedRegions() throws Exception {
+    setupCluster();
+    final TableName tableName = TableName.valueOf(this.name.getMethodName());
+    String snapshotName = tableName.getNameAsString() + "_snapshot";
+    Configuration conf = UTIL.getConfiguration();
+    try (Admin admin = UTIL.getConnection().getAdmin()) {
+      // disable compaction
+      admin.compactionSwitch(false,
+        admin.getRegionServers().stream().map(s -> s.getServerName()).collect(Collectors.toList()));
+      // create table
+      Table table = UTIL.createTable(tableName, FAMILIES, 1, bbb, yyy, 3);
+      List<RegionInfo> regions = admin.getRegions(tableName);
+      Assert.assertEquals(3, regions.size());
+      // write some data
+      UTIL.loadTable(table, FAMILIES);
+      // merge region
+      admin.mergeRegionsAsync(new byte[][] { regions.get(0).getEncodedNameAsBytes(),
+          regions.get(1).getEncodedNameAsBytes() },
+        false).get();
+      regions = admin.getRegions(tableName);
+      Assert.assertEquals(2, regions.size());
+      // snapshot
+      admin.snapshot(snapshotName, tableName);
+      // verify snapshot
+      try (TableSnapshotScanner scanner =
+          new TableSnapshotScanner(conf, UTIL.getDataTestDirOnTestFS(snapshotName), snapshotName,
+              new Scan().withStartRow(bbb).withStopRow(yyy))) {
+        verifyScanner(scanner, bbb, yyy);
+      }
+      // drop table
+      admin.disableTable(tableName);
+      admin.deleteTable(tableName);
+      // verify snapshot
+      try (TableSnapshotScanner scanner =
+          new TableSnapshotScanner(conf, UTIL.getDataTestDirOnTestFS(snapshotName), snapshotName,
+              new Scan().withStartRow(bbb).withStopRow(yyy))) {
+        verifyScanner(scanner, bbb, yyy);
+      }
+    }
+  }
+
   private void traverseAndSetFileTime(Path path, long time) throws IOException {
     fs.setTimes(path, time, -1);
     if (fs.isDirectory(path)) {