HBASE-21977 Skip replay WAL and update seqid when open regions restored from snapshot

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

hbase-server/src/main/java/org/apache/hadoop/hbase/client/ClientSideRegionScanner.java

@@ -60,6 +60,7 @@ public class ClientSideRegionScanner extends AbstractClientScanner {
     // open region from the snapshot directory
     region = HRegion.newHRegion(FSUtils.getTableDir(rootDir, htd.getTableName()), null, fs, conf,
       hri, htd, null);
+    region.setRestoredRegion(true);
     // we won't initialize the MobFileCache when not running in RS process. so provided an
     // initialized cache. Consider the case: an CF was set from an mob to non-mob. if we only
     // initialize cache for MOB region, NPE from HMobStore will still happen. So Initialize the

hbase-server/src/main/java/org/apache/hadoop/hbase/regionserver/HRegion.java

@@ -338,6 +338,13 @@ public class HRegion implements HeapSize, PropagatingConfigurationObserver, Regi
   private Path regionDir;
   private FileSystem walFS;
 
+  // set to true if the region is restored from snapshot
+  private boolean isRestoredRegion = false;
+
+  public void setRestoredRegion(boolean restoredRegion) {
+    isRestoredRegion = restoredRegion;
+  }
+
   // The internal wait duration to acquire a lock before read/update
   // from the region. It is not per row. The purpose of this wait time
   // is to avoid waiting a long time while the region is busy, so that
@@ -951,7 +958,7 @@ public class HRegion implements HeapSize, PropagatingConfigurationObserver, Regi
     status.setStatus("Initializing all the Stores");
     long maxSeqId = initializeStores(reporter, status);
     this.mvcc.advanceTo(maxSeqId);
-    if (ServerRegionReplicaUtil.shouldReplayRecoveredEdits(this)) {
+    if (!isRestoredRegion && ServerRegionReplicaUtil.shouldReplayRecoveredEdits(this)) {
       Collection<HStore> stores = this.stores.values();
       try {
         // update the stores that we are replaying
@@ -1000,15 +1007,18 @@ public class HRegion implements HeapSize, PropagatingConfigurationObserver, Regi
 
     // Use maximum of log sequenceid or that which was found in stores
     // (particularly if no recovered edits, seqid will be -1).
-    long maxSeqIdFromFile =
+    long nextSeqId = maxSeqId + 1;
-        WALSplitter.getMaxRegionSequenceId(getWalFileSystem(), getWALRegionDirOfDefaultReplica());
+    if (!isRestoredRegion) {
-    long nextSeqId = Math.max(maxSeqId, maxSeqIdFromFile) + 1;
+      long maxSeqIdFromFile =
-    // The openSeqNum will always be increase even for read only region, as we rely on it to
+          WALSplitter.getMaxRegionSequenceId(getWalFileSystem(), getWALRegionDirOfDefaultReplica());
-    // determine whether a region has been successfully reopend, so here we always need to update
+      nextSeqId = Math.max(maxSeqId, maxSeqIdFromFile) + 1;
-    // the max sequence id file.
+      // The openSeqNum will always be increase even for read only region, as we rely on it to
-    if (RegionReplicaUtil.isDefaultReplica(getRegionInfo())) {
+      // determine whether a region has been successfully reopend, so here we always need to update
-      LOG.debug("writing seq id for {}", this.getRegionInfo().getEncodedName());
+      // the max sequence id file.
-      WALSplitter.writeRegionSequenceIdFile(getWalFileSystem(), getWALRegionDir(), nextSeqId - 1);
+      if (RegionReplicaUtil.isDefaultReplica(getRegionInfo())) {
+        LOG.debug("writing seq id for {}", this.getRegionInfo().getEncodedName());
+        WALSplitter.writeRegionSequenceIdFile(getWalFileSystem(), getWALRegionDir(), nextSeqId - 1);
+      }
     }
 
     LOG.info("Opened {}; next sequenceid={}", this.getRegionInfo().getShortNameToLog(), nextSeqId);

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

@@ -31,12 +31,14 @@ import org.apache.hadoop.hbase.HBaseClassTestRule;
 import org.apache.hadoop.hbase.HBaseTestingUtility;
 import org.apache.hadoop.hbase.HConstants;
 import org.apache.hadoop.hbase.TableName;
+import org.apache.hadoop.hbase.client.RegionInfo;
 import org.apache.hadoop.hbase.client.Table;
 import org.apache.hadoop.hbase.client.TableDescriptor;
 import org.apache.hadoop.hbase.errorhandling.ForeignExceptionDispatcher;
 import org.apache.hadoop.hbase.io.HFileLink;
 import org.apache.hadoop.hbase.mob.MobUtils;
 import org.apache.hadoop.hbase.monitoring.MonitoredTask;
+import org.apache.hadoop.hbase.regionserver.HRegion;
 import org.apache.hadoop.hbase.regionserver.StoreFileInfo;
 import org.apache.hadoop.hbase.snapshot.SnapshotTestingUtils.SnapshotMock;
 import org.apache.hadoop.hbase.testclassification.MediumTests;
@@ -45,6 +47,7 @@ import org.apache.hadoop.hbase.util.Bytes;
 import org.apache.hadoop.hbase.util.CommonFSUtils;
 import org.apache.hadoop.hbase.util.FSTableDescriptors;
 import org.apache.hadoop.hbase.util.FSUtils;
+import org.apache.hadoop.hbase.wal.WALSplitter;
 import org.junit.After;
 import org.junit.AfterClass;
 import org.junit.Assert;
@@ -136,6 +139,45 @@ public class TestRestoreSnapshotHelper {
     checkNoHFileLinkInTableDir(tableName);
   }
 
+  @Test
+  public void testSkipReplayAndUpdateSeqId() throws Exception {
+    rootDir = TEST_UTIL.getDefaultRootDirPath();
+    FSUtils.setRootDir(conf, rootDir);
+    TableName tableName = TableName.valueOf("testSkipReplayAndUpdateSeqId");
+    String snapshotName = "testSkipReplayAndUpdateSeqId";
+    createTableAndSnapshot(tableName, snapshotName);
+    // put some data in the table
+    Table table = TEST_UTIL.getConnection().getTable(tableName);
+    TEST_UTIL.loadTable(table, Bytes.toBytes("A"));
+
+    Configuration conf = TEST_UTIL.getConfiguration();
+    Path rootDir = FSUtils.getRootDir(conf);
+    Path restoreDir = new Path("/hbase/.tmp-restore/testScannerWithRestoreScanner2");
+    // restore snapshot.
+    final RestoreSnapshotHelper.RestoreMetaChanges meta =
+        RestoreSnapshotHelper.copySnapshotForScanner(conf, fs, rootDir, restoreDir, snapshotName);
+    TableDescriptor htd = meta.getTableDescriptor();
+    final List<RegionInfo> restoredRegions = meta.getRegionsToAdd();
+    for (RegionInfo restoredRegion : restoredRegions) {
+      // open restored region
+      HRegion region = HRegion.newHRegion(FSUtils.getTableDir(restoreDir, tableName), null, fs,
+        conf, restoredRegion, htd, null);
+      // set restore flag
+      region.setRestoredRegion(true);
+      region.initialize();
+      Path recoveredEdit =
+          FSUtils.getWALRegionDir(conf, tableName, region.getRegionInfo().getEncodedName());
+      long maxSeqId = WALSplitter.getMaxRegionSequenceId(fs, recoveredEdit);
+
+      // open restored region without set restored flag
+      HRegion region2 = HRegion.newHRegion(FSUtils.getTableDir(restoreDir, tableName), null, fs,
+        conf, restoredRegion, htd, null);
+      region2.initialize();
+      long maxSeqId2 = WALSplitter.getMaxRegionSequenceId(fs, recoveredEdit);
+      Assert.assertTrue(maxSeqId2 > maxSeqId);
+    }
+  }
+
   protected void createTableAndSnapshot(TableName tableName, String snapshotName)
       throws IOException {
     byte[] column = Bytes.toBytes("A");