HBASE-26187 Write straight into the store directory when Splitting an…

hbase-server/src/main/java/org/apache/hadoop/hbase/master/assignment/MergeTableRegionsProcedure.java

@@ -582,34 +582,29 @@ private void setRegionStateToMerging(final MasterProcedureEnv env) {
    */
   private void createMergedRegion(final MasterProcedureEnv env) throws IOException {
     final MasterFileSystem mfs = env.getMasterServices().getMasterFileSystem();
-    final Path tabledir = CommonFSUtils.getTableDir(mfs.getRootDir(), regionsToMerge[0].getTable());
+    final Path tableDir = CommonFSUtils.getTableDir(mfs.getRootDir(), regionsToMerge[0].getTable());
     final FileSystem fs = mfs.getFileSystem();
-    HRegionFileSystem mergeRegionFs = null;
+
+    HRegionFileSystem mergeRegionFs = HRegionFileSystem.createRegionOnFileSystem(
+      env.getMasterConfiguration(), fs, tableDir, mergedRegion);
+
     for (RegionInfo ri: this.regionsToMerge) {
       HRegionFileSystem regionFs = HRegionFileSystem.openRegionFromFileSystem(
-          env.getMasterConfiguration(), fs, tabledir, ri, false);
-      if (mergeRegionFs == null) {
-        mergeRegionFs = regionFs;
-        mergeRegionFs.createMergesDir();
-      }
-      mergeStoreFiles(env, regionFs, mergeRegionFs.getMergesDir());
+          env.getMasterConfiguration(), fs, tableDir, ri, false);
+      mergeStoreFiles(env, regionFs, mergeRegionFs, mergedRegion);
     }
     assert mergeRegionFs != null;
-    mergeRegionFs.commitMergedRegion(mergedRegion);
+    mergeRegionFs.commitMergedRegion();
 
     // Prepare to create merged regions
     env.getAssignmentManager().getRegionStates().
         getOrCreateRegionStateNode(mergedRegion).setState(State.MERGING_NEW);
   }
 
-  /**
-   * Create reference file(s) to parent region hfiles in the <code>mergeDir</code>
-   * @param regionFs merge parent region file system
-   * @param mergeDir the temp directory in which we are accumulating references.
-   */
-  private void mergeStoreFiles(final MasterProcedureEnv env, final HRegionFileSystem regionFs,
-      final Path mergeDir) throws IOException {
-    final TableDescriptor htd = env.getMasterServices().getTableDescriptors().get(getTableName());
+  private void mergeStoreFiles(MasterProcedureEnv env, HRegionFileSystem regionFs,
+    HRegionFileSystem mergeRegionFs, RegionInfo mergedRegion) throws IOException {
+    final TableDescriptor htd = env.getMasterServices().getTableDescriptors()
+      .get(mergedRegion.getTable());
     for (ColumnFamilyDescriptor hcd : htd.getColumnFamilies()) {
       String family = hcd.getNameAsString();
       final Collection<StoreFileInfo> storeFiles = regionFs.getStoreFiles(family);
@@ -618,8 +613,8 @@ private void mergeStoreFiles(final MasterProcedureEnv env, final HRegionFileSyst
           // Create reference file(s) to parent region file here in mergedDir.
           // As this procedure is running on master, use CacheConfig.DISABLED means
           // don't cache any block.
-          regionFs.mergeStoreFile(mergedRegion, family, new HStoreFile(
-              storeFileInfo, hcd.getBloomFilterType(), CacheConfig.DISABLED), mergeDir);
+          mergeRegionFs.mergeStoreFile(regionFs.getRegionInfo(), family,
+            new HStoreFile(storeFileInfo, hcd.getBloomFilterType(), CacheConfig.DISABLED));
         }
       }
     }

hbase-server/src/main/java/org/apache/hadoop/hbase/master/assignment/SplitTableRegionProcedure.java

@@ -372,7 +372,7 @@ protected void rollbackState(final MasterProcedureEnv env, final SplitTableRegio
           break;
         case SPLIT_TABLE_REGION_CREATE_DAUGHTER_REGIONS:
         case SPLIT_TABLE_REGION_WRITE_MAX_SEQUENCE_ID_FILE:
-          // Doing nothing, as re-open parent region would clean up daughter region directories.
+          deleteDaughterRegions(env);
           break;
         case SPLIT_TABLE_REGIONS_CHECK_CLOSED_REGIONS:
           // Doing nothing, in SPLIT_TABLE_REGION_CLOSE_PARENT_REGION,
@@ -624,7 +624,6 @@ public void createDaughterRegions(final MasterProcedureEnv env) throws IOExcepti
 
     assertReferenceFileCount(fs, expectedReferences.getFirst(),
       regionFs.getSplitsDir(daughterOneRI));
-    //Move the files from the temporary .splits to the final /table/region directory
     regionFs.commitDaughterRegion(daughterOneRI);
     assertReferenceFileCount(fs, expectedReferences.getFirst(),
       new Path(tabledir, daughterOneRI.getEncodedName()));
@@ -636,6 +635,15 @@ public void createDaughterRegions(final MasterProcedureEnv env) throws IOExcepti
       new Path(tabledir, daughterTwoRI.getEncodedName()));
   }
 
+  private void deleteDaughterRegions(final MasterProcedureEnv env) throws IOException {
+    final MasterFileSystem mfs = env.getMasterServices().getMasterFileSystem();
+    final Path tabledir = CommonFSUtils.getTableDir(mfs.getRootDir(), getTableName());
+    HRegionFileSystem.deleteRegionFromFileSystem(env.getMasterConfiguration(),
+      mfs.getFileSystem(), tabledir, daughterOneRI);
+    HRegionFileSystem.deleteRegionFromFileSystem(env.getMasterConfiguration(),
+      mfs.getFileSystem(), tabledir, daughterTwoRI);
+  }
+
   /**
    * Create Split directory
    * @param env MasterProcedureEnv
@@ -648,9 +656,11 @@ private Pair<Integer, Integer> splitStoreFiles(final MasterProcedureEnv env,
     // there's files to split. It then fires up everything, waits for
     // completion and finally checks for any exception
     //
-    // Note: splitStoreFiles creates daughter region dirs under the parent splits dir
-    // Nothing to unroll here if failure -- re-run createSplitsDir will
-    // clean this up.
+    // Note: From HBASE-26187, splitStoreFiles now creates daughter region dirs straight under the
+    // table dir. In case of failure, the proc would go through this again, already existing
+    // region dirs and split files would just be ignored, new split files should get created.
+    // Cleanups for failed splits that couldn't retry would be done by CatalogJanitor, as there
+    // would be no entry for the region in meta.
     int nbFiles = 0;
     final Map<String, Collection<StoreFileInfo>> files =
         new HashMap<String, Collection<StoreFileInfo>>(htd.getColumnFamilyCount());

hbase-server/src/main/java/org/apache/hadoop/hbase/master/janitor/CatalogJanitor.java

@@ -182,9 +182,7 @@ public int scan() throws IOException {
       for (Map.Entry<RegionInfo, Result> e : mergedRegions.entrySet()) {
         if (this.services.isInMaintenanceMode()) {
           // Stop cleaning if the master is in maintenance mode
-          if (LOG.isDebugEnabled()) {
-            LOG.debug("In maintenence mode, not cleaning");
-          }
+          LOG.debug("In maintenence mode, not cleaning");
           break;
         }
 

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

@@ -1023,16 +1023,6 @@ private long initializeRegionInternals(final CancelableProgressable reporter,
       fs.cleanupTempDir();
     }
 
-    if (this.writestate.writesEnabled) {
-      status.setStatus("Cleaning up detritus from prior splits");
-      // Get rid of any splits or merges that were lost in-progress.  Clean out
-      // these directories here on open.  We may be opening a region that was
-      // being split but we crashed in the middle of it all.
-      LOG.debug("Cleaning up detritus for " + this.getRegionInfo().getEncodedName());
-      fs.cleanupAnySplitDetritus();
-      fs.cleanupMergesDir();
-    }
-
     // Initialize split policy
     this.splitPolicy = RegionSplitPolicy.create(this, conf);