HBASE-19478 Utilize multi-get to speed up WAL file checking in BackupLogCleaner (Toshihiro Suzuki)

hbase-backup/src/main/java/org/apache/hadoop/hbase/backup/impl/BackupSystemTable.java

@@ -37,6 +37,7 @@ import java.util.stream.Collectors;
 import org.apache.commons.lang3.ArrayUtils;
 import org.apache.commons.lang3.StringUtils;
 import org.apache.hadoop.conf.Configuration;
+import org.apache.hadoop.fs.FileStatus;
 import org.apache.hadoop.fs.Path;
 import org.apache.hadoop.hbase.Cell;
 import org.apache.hadoop.hbase.CellUtil;
@@ -1090,6 +1091,47 @@ public final class BackupSystemTable implements Closeable {
     }
   }
 
+  /**
+   * Check if WAL file is eligible for deletion using multi-get
+   * @param files names of a file to check
+   * @return map of results
+   *         (key: FileStatus object. value: true if the file is deletable, false otherwise)
+   * @throws IOException exception
+   */
+  public Map<FileStatus, Boolean> areWALFilesDeletable(Iterable<FileStatus> files)
+    throws IOException {
+    final int BUF_SIZE = 100;
+
+    Map<FileStatus, Boolean> ret = new HashMap<>();
+    try (Table table = connection.getTable(tableName)) {
+      List<Get> getBuffer = new ArrayList<>();
+      List<FileStatus> fileStatuses = new ArrayList<>();
+
+      for (FileStatus file : files) {
+        String wal = file.getPath().toString();
+        Get get = createGetForCheckWALFile(wal);
+        getBuffer.add(get);
+        fileStatuses.add(file);
+        if (getBuffer.size() >= BUF_SIZE) {
+          Result[] results = table.get(getBuffer);
+          for (int i = 0; i < results.length; i++) {
+            ret.put(fileStatuses.get(i), !results[i].isEmpty());
+          }
+          getBuffer.clear();
+          fileStatuses.clear();
+        }
+      }
+
+      if (!getBuffer.isEmpty()) {
+        Result[] results = table.get(getBuffer);
+        for (int i = 0; i < results.length; i++) {
+          ret.put(fileStatuses.get(i), !results[i].isEmpty());
+        }
+      }
+    }
+    return ret;
+  }
+
   /**
    * Checks if we have at least one backup session in backup system table This API is used by
    * BackupLogCleaner

hbase-backup/src/main/java/org/apache/hadoop/hbase/backup/master/BackupLogCleaner.java

@@ -96,14 +96,18 @@ public class BackupLogCleaner extends BaseLogCleanerDelegate {
         return files;
       }
 
-      for (FileStatus file : files) {
+      Map<FileStatus, Boolean> walFilesDeletableMap = table.areWALFilesDeletable(files);
+      for (Map.Entry<FileStatus, Boolean> entry: walFilesDeletableMap.entrySet()) {
+        FileStatus file = entry.getKey();
         String wal = file.getPath().toString();
-        boolean logInSystemTable = table.isWALFileDeletable(wal);
+        boolean deletable = entry.getValue();
+        if (deletable) {
           if (LOG.isDebugEnabled()) {
-          if (logInSystemTable) {
             LOG.debug("Found log file in backup system table, deleting: " + wal);
+          }
           list.add(file);
         } else {
+          if (LOG.isDebugEnabled()) {
             LOG.debug("Didn't find this log in backup system table, keeping: " + wal);
           }
         }

hbase-backup/src/test/java/org/apache/hadoop/hbase/backup/TestBackupSystemTable.java

@@ -32,10 +32,13 @@ import java.util.HashMap;
 import java.util.HashSet;
 import java.util.Iterator;
 import java.util.List;
+import java.util.Map;
 import java.util.Set;
 import java.util.TreeSet;
 
 import org.apache.hadoop.conf.Configuration;
+import org.apache.hadoop.fs.FileStatus;
+import org.apache.hadoop.fs.Path;
 import org.apache.hadoop.hbase.HBaseTestingUtility;
 import org.apache.hadoop.hbase.MiniHBaseCluster;
 import org.apache.hadoop.hbase.TableName;
@@ -335,6 +338,25 @@ public class TestBackupSystemTable {
     assertTrue(table.isWALFileDeletable(files.get(2)));
     assertFalse(table.isWALFileDeletable(newFile));
 
+    // test for isWALFilesDeletable
+    List<FileStatus> fileStatues = new ArrayList<>();
+    for (String file : files) {
+      FileStatus fileStatus = new FileStatus();
+      fileStatus.setPath(new Path(file));
+      fileStatues.add(fileStatus);
+    }
+
+    FileStatus newFileStatus = new FileStatus();
+    newFileStatus.setPath(new Path(newFile));
+    fileStatues.add(newFileStatus);
+
+    Map<FileStatus, Boolean> walFilesDeletableMap = table.areWALFilesDeletable(fileStatues);
+
+    assertTrue(walFilesDeletableMap.get(fileStatues.get(0)));
+    assertTrue(walFilesDeletableMap.get(fileStatues.get(1)));
+    assertTrue(walFilesDeletableMap.get(fileStatues.get(2)));
+    assertFalse(walFilesDeletableMap.get(newFileStatus));
+
     cleanBackupTable();
   }