server/base/src/main/java/org/apache/accumulo/server/metadata/ServerAmpleImpl.java - accumulo - Git at Google

 /*
  * 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
  *
  *   https://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.accumulo.server.metadata;

 import static java.nio.charset.StandardCharsets.UTF_8;
 import static org.apache.accumulo.core.metadata.RootTable.ZROOT_TABLET_GC_CANDIDATES;
 import static org.apache.accumulo.server.util.MetadataTableUtil.EMPTY_TEXT;

 import java.util.Collection;
 import java.util.Iterator;
 import java.util.Map;
 import java.util.Objects;
 import java.util.Set;
 import java.util.UUID;
 import java.util.function.Consumer;
 import java.util.stream.Collectors;
 import java.util.stream.Stream;
 import java.util.stream.StreamSupport;

 import org.apache.accumulo.core.client.BatchWriter;
 import org.apache.accumulo.core.client.IsolatedScanner;
 import org.apache.accumulo.core.client.MutationsRejectedException;
 import org.apache.accumulo.core.client.Scanner;
 import org.apache.accumulo.core.client.TableNotFoundException;
 import org.apache.accumulo.core.data.Key;
 import org.apache.accumulo.core.data.Mutation;
 import org.apache.accumulo.core.data.Range;
 import org.apache.accumulo.core.data.TableId;
 import org.apache.accumulo.core.data.Value;
 import org.apache.accumulo.core.dataImpl.KeyExtent;
 import org.apache.accumulo.core.fate.FateTxId;
 import org.apache.accumulo.core.gc.GcCandidate;
 import org.apache.accumulo.core.gc.ReferenceFile;
 import org.apache.accumulo.core.metadata.MetadataTable;
 import org.apache.accumulo.core.metadata.RootTable;
 import org.apache.accumulo.core.metadata.ScanServerRefTabletFile;
 import org.apache.accumulo.core.metadata.StoredTabletFile;
 import org.apache.accumulo.core.metadata.ValidationUtil;
 import org.apache.accumulo.core.metadata.schema.Ample;
 import org.apache.accumulo.core.metadata.schema.AmpleImpl;
 import org.apache.accumulo.core.metadata.schema.ExternalCompactionFinalState;
 import org.apache.accumulo.core.metadata.schema.ExternalCompactionId;
 import org.apache.accumulo.core.metadata.schema.MetadataSchema.BlipSection;
 import org.apache.accumulo.core.metadata.schema.MetadataSchema.DeletesSection;
 import org.apache.accumulo.core.metadata.schema.MetadataSchema.DeletesSection.SkewedKeyValue;
 import org.apache.accumulo.core.metadata.schema.MetadataSchema.ExternalCompactionSection;
 import org.apache.accumulo.core.metadata.schema.MetadataSchema.ScanServerFileReferenceSection;
 import org.apache.accumulo.core.metadata.schema.MetadataSchema.TabletsSection.BulkFileColumnFamily;
 import org.apache.accumulo.core.security.Authorizations;
 import org.apache.accumulo.server.ServerContext;
 import org.apache.hadoop.io.Text;
 import org.apache.zookeeper.KeeperException;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;

 import com.google.common.base.Preconditions;

 public class ServerAmpleImpl extends AmpleImpl implements Ample {

   private static Logger log = LoggerFactory.getLogger(ServerAmpleImpl.class);

   private ServerContext context;

   public ServerAmpleImpl(ServerContext context) {
     super(context);
     this.context = context;
   }

   @Override
   public Ample.TabletMutator mutateTablet(KeyExtent extent) {
     TabletsMutator tmi = mutateTablets();
     Ample.TabletMutator tabletMutator = tmi.mutateTablet(extent);
     ((TabletMutatorBase) tabletMutator).setCloseAfterMutate(tmi);
     return tabletMutator;
   }

   @Override
   public TabletsMutator mutateTablets() {
     return new TabletsMutatorImpl(context);
   }

   private void mutateRootGcCandidates(Consumer<RootGcCandidates> mutator) {
     String zpath = context.getZooKeeperRoot() + ZROOT_TABLET_GC_CANDIDATES;
     try {
       context.getZooReaderWriter().mutateOrCreate(zpath, new byte[0], currVal -> {
         String currJson = new String(currVal, UTF_8);
         RootGcCandidates rgcc = new RootGcCandidates(currJson);
         log.debug("Root GC candidates before change : {}", currJson);
         mutator.accept(rgcc);
         String newJson = rgcc.toJson();
         log.debug("Root GC candidates after change  : {}", newJson);
         if (newJson.length() > 262_144) {
           log.warn(
               "Root tablet deletion candidates stored in ZK at {} are getting large ({} bytes), is"
                   + " Accumulo GC process running?  Large nodes may cause problems for Zookeeper!",
               zpath, newJson.length());
         }
         return newJson.getBytes(UTF_8);
       });
     } catch (Exception e) {
       throw new RuntimeException(e);
     }
   }

   @Override
   public void putGcCandidates(TableId tableId, Collection<StoredTabletFile> candidates) {

     if (RootTable.ID.equals(tableId)) {
       mutateRootGcCandidates(rgcc -> rgcc.add(candidates.stream()));
       return;
     }

     try (BatchWriter writer = context.createBatchWriter(DataLevel.of(tableId).metaTable())) {
       for (StoredTabletFile file : candidates) {
         writer.addMutation(createDeleteMutation(file));
       }
     } catch (MutationsRejectedException | TableNotFoundException e) {
       throw new RuntimeException(e);
     }
   }

   @Override
   public void putGcFileAndDirCandidates(TableId tableId, Collection<ReferenceFile> candidates) {

     if (DataLevel.of(tableId) == DataLevel.ROOT) {
       // Directories are unexpected for the root tablet, so convert to stored tablet file
       mutateRootGcCandidates(rgcc -> rgcc.add(candidates.stream()
           .map(reference -> new StoredTabletFile(reference.getMetadataEntry()))));
       return;
     }

     try (BatchWriter writer = context.createBatchWriter(DataLevel.of(tableId).metaTable())) {
       for (var fileOrDir : candidates) {
         writer.addMutation(createDeleteMutation(fileOrDir));
       }
     } catch (MutationsRejectedException | TableNotFoundException e) {
       throw new RuntimeException(e);
     }
   }

   @Override
   public void addBulkLoadInProgressFlag(String path, long fateTxid) {

     // Bulk Import operations are not supported on the metadata table, so no entries will ever be
     // required on the root table.
     Mutation m = new Mutation(BlipSection.getRowPrefix() + path);
     m.put(EMPTY_TEXT, EMPTY_TEXT, new Value(FateTxId.formatTid(fateTxid)));

     try (BatchWriter bw = context.createBatchWriter(MetadataTable.NAME)) {
       bw.addMutation(m);
     } catch (MutationsRejectedException | TableNotFoundException e) {
       throw new RuntimeException(e);
     }
   }

   @Override
   public void removeBulkLoadInProgressFlag(String path) {

     // Bulk Import operations are not supported on the metadata table, so no entries will ever be
     // required on the root table.
     Mutation m = new Mutation(BlipSection.getRowPrefix() + path);
     m.putDelete(EMPTY_TEXT, EMPTY_TEXT);

     try (BatchWriter bw = context.createBatchWriter(MetadataTable.NAME)) {
       bw.addMutation(m);
     } catch (MutationsRejectedException | TableNotFoundException e) {
       throw new RuntimeException(e);
     }
   }

   @Override
   public void removeBulkLoadEntries(TableId tableId, long tid, Text firstSplit, Text lastSplit) {
     Preconditions.checkArgument(DataLevel.of(tableId) == DataLevel.USER);
     try (
         Scanner mscanner =
             new IsolatedScanner(context.createScanner(MetadataTable.NAME, Authorizations.EMPTY));
         BatchWriter bw = context.createBatchWriter(MetadataTable.NAME)) {
       mscanner.setRange(new KeyExtent(tableId, lastSplit, firstSplit).toMetaRange());
       mscanner.fetchColumnFamily(BulkFileColumnFamily.NAME);

       for (Map.Entry<Key,Value> entry : mscanner) {
         log.trace("Looking at entry {} with tid {}", entry, tid);
         long entryTid = BulkFileColumnFamily.getBulkLoadTid(entry.getValue());
         if (tid == entryTid) {
           log.trace("deleting entry {}", entry);
           Key key = entry.getKey();
           Mutation m = new Mutation(key.getRow());
           m.putDelete(key.getColumnFamily(), key.getColumnQualifier());
           bw.addMutation(m);
         }
       }
     } catch (MutationsRejectedException | TableNotFoundException e) {
       throw new RuntimeException(e);
     }
   }

   @Override
   public void deleteGcCandidates(DataLevel level, Collection<GcCandidate> candidates,
       GcCandidateType type) {

     if (level == DataLevel.ROOT) {
       if (type == GcCandidateType.INUSE) {
         // Since there is only a single root tablet, supporting INUSE candidate deletions would add
         // additional code complexity without any substantial benefit.
         // Therefore, deletion of root INUSE candidates is not supported.
         return;
       }
       mutateRootGcCandidates(rgcc -> rgcc.remove(candidates.stream()));
       return;
     }

     try (BatchWriter writer = context.createBatchWriter(level.metaTable())) {
       if (type == GcCandidateType.VALID) {
         for (GcCandidate candidate : candidates) {
           Mutation m = new Mutation(DeletesSection.encodeRow(candidate.getPath()));
           // Removes all versions of the candidate to avoid reprocessing deleted file entries
           m.putDelete(EMPTY_TEXT, EMPTY_TEXT);
           writer.addMutation(m);
         }
       } else {
         for (GcCandidate candidate : candidates) {
           Mutation m = new Mutation(DeletesSection.encodeRow(candidate.getPath()));
           // Removes this and older versions while allowing newer candidate versions to persist
           m.putDelete(EMPTY_TEXT, EMPTY_TEXT, candidate.getUid());
           writer.addMutation(m);
         }
       }
     } catch (MutationsRejectedException | TableNotFoundException e) {
       throw new RuntimeException(e);
     }
   }

   @Override
   public Iterator<GcCandidate> getGcCandidates(DataLevel level) {
     if (level == DataLevel.ROOT) {
       var zooReader = context.getZooReader();
       byte[] jsonBytes;
       try {
         jsonBytes =
             zooReader.getData(context.getZooKeeperRoot() + RootTable.ZROOT_TABLET_GC_CANDIDATES);
       } catch (KeeperException | InterruptedException e) {
         throw new RuntimeException(e);
       }
       return new RootGcCandidates(new String(jsonBytes, UTF_8)).sortedStream().iterator();
     } else if (level == DataLevel.METADATA || level == DataLevel.USER) {
       Range range = DeletesSection.getRange();

       Scanner scanner;
       try {
         scanner = context.createScanner(level.metaTable(), Authorizations.EMPTY);
       } catch (TableNotFoundException e) {
         throw new RuntimeException(e);
       }
       scanner.setRange(range);
       return scanner.stream().filter(entry -> entry.getValue().equals(SkewedKeyValue.NAME))
           .map(
               entry -> new GcCandidate(DeletesSection.decodeRow(entry.getKey().getRow().toString()),
                   entry.getKey().getTimestamp()))
           .iterator();
     } else {
       throw new IllegalArgumentException();
     }
   }

   @Override
   public Mutation createDeleteMutation(ReferenceFile tabletFilePathToRemove) {
     return createDelMutation(ValidationUtil.validate(tabletFilePathToRemove).getMetadataEntry());
   }

   public Mutation createDeleteMutation(StoredTabletFile pathToRemove) {
     return createDelMutation(pathToRemove.getMetaUpdateDelete());
   }

   private Mutation createDelMutation(String path) {
     Mutation delFlag = new Mutation(new Text(DeletesSection.encodeRow(path)));
     delFlag.put(EMPTY_TEXT, EMPTY_TEXT, DeletesSection.SkewedKeyValue.NAME);
     return delFlag;
   }

   @Override
   public void
       putExternalCompactionFinalStates(Collection<ExternalCompactionFinalState> finalStates) {
     try (BatchWriter writer = context.createBatchWriter(DataLevel.USER.metaTable())) {
       String prefix = ExternalCompactionSection.getRowPrefix();
       for (ExternalCompactionFinalState finalState : finalStates) {
         Mutation m = new Mutation(prefix + finalState.getExternalCompactionId().canonical());
         m.put("", "", finalState.toJson());
         writer.addMutation(m);
       }
     } catch (MutationsRejectedException | TableNotFoundException e) {
       throw new RuntimeException(e);
     }
   }

   @Override
   public Stream<ExternalCompactionFinalState> getExternalCompactionFinalStates() {
     Scanner scanner;
     try {
       scanner = context.createScanner(DataLevel.USER.metaTable(), Authorizations.EMPTY);
     } catch (TableNotFoundException e) {
       throw new RuntimeException(e);
     }

     scanner.setRange(ExternalCompactionSection.getRange());
     int pLen = ExternalCompactionSection.getRowPrefix().length();
     return scanner.stream()
         .map(e -> ExternalCompactionFinalState.fromJson(
             ExternalCompactionId.of(e.getKey().getRowData().toString().substring(pLen)),
             e.getValue().toString()));
   }

   @Override
   public void
       deleteExternalCompactionFinalStates(Collection<ExternalCompactionId> statusesToDelete) {
     try (BatchWriter writer = context.createBatchWriter(DataLevel.USER.metaTable())) {
       String prefix = ExternalCompactionSection.getRowPrefix();
       for (ExternalCompactionId ecid : statusesToDelete) {
         Mutation m = new Mutation(prefix + ecid.canonical());
         m.putDelete(EMPTY_TEXT, EMPTY_TEXT);
         writer.addMutation(m);
       }
       log.debug("Deleted external compaction final state entries for external compactions: {}",
           statusesToDelete);
     } catch (MutationsRejectedException | TableNotFoundException e) {
       throw new RuntimeException(e);
     }
   }

   @Override
   public void putScanServerFileReferences(Collection<ScanServerRefTabletFile> scanRefs) {
     try (BatchWriter writer = context.createBatchWriter(DataLevel.USER.metaTable())) {
       String prefix = ScanServerFileReferenceSection.getRowPrefix();
       for (ScanServerRefTabletFile ref : scanRefs) {
         Mutation m = new Mutation(prefix + ref.getRowSuffix());
         m.put(ref.getServerAddress(), ref.getServerLockUUID(), ref.getValue());
         writer.addMutation(m);
       }
     } catch (MutationsRejectedException | TableNotFoundException e) {
       throw new IllegalStateException(
           "Error inserting scan server file references into " + DataLevel.USER.metaTable(), e);
     }
   }

   @Override
   public Stream<ScanServerRefTabletFile> getScanServerFileReferences() {
     try {
       Scanner scanner = context.createScanner(DataLevel.USER.metaTable(), Authorizations.EMPTY);
       scanner.setRange(ScanServerFileReferenceSection.getRange());
       int pLen = ScanServerFileReferenceSection.getRowPrefix().length();
       return StreamSupport.stream(scanner.spliterator(), false)
           .map(e -> new ScanServerRefTabletFile(e.getKey().getRowData().toString().substring(pLen),
               e.getKey().getColumnFamily(), e.getKey().getColumnQualifier()));
     } catch (TableNotFoundException e) {
       throw new IllegalStateException(DataLevel.USER.metaTable() + " not found!", e);
     }
   }

   @Override
   public void deleteScanServerFileReferences(String serverAddress, UUID scanServerLockUUID) {
     Objects.requireNonNull(serverAddress, "Server address must be supplied");
     Objects.requireNonNull(scanServerLockUUID, "Server uuid must be supplied");
     try (
         Scanner scanner = context.createScanner(DataLevel.USER.metaTable(), Authorizations.EMPTY)) {
       scanner.setRange(ScanServerFileReferenceSection.getRange());
       scanner.fetchColumn(new Text(serverAddress), new Text(scanServerLockUUID.toString()));

       int pLen = ScanServerFileReferenceSection.getRowPrefix().length();
       Set<ScanServerRefTabletFile> refsToDelete = StreamSupport.stream(scanner.spliterator(), false)
           .map(e -> new ScanServerRefTabletFile(e.getKey().getRowData().toString().substring(pLen),
               e.getKey().getColumnFamily(), e.getKey().getColumnQualifier()))
           .collect(Collectors.toSet());

       if (!refsToDelete.isEmpty()) {
         this.deleteScanServerFileReferences(refsToDelete);
       }
     } catch (TableNotFoundException e) {
       throw new IllegalStateException(DataLevel.USER.metaTable() + " not found!", e);
     }
   }

   @Override
   public void deleteScanServerFileReferences(Collection<ScanServerRefTabletFile> refsToDelete) {
     try (BatchWriter writer = context.createBatchWriter(DataLevel.USER.metaTable())) {
       String prefix = ScanServerFileReferenceSection.getRowPrefix();
       for (ScanServerRefTabletFile ref : refsToDelete) {
         Mutation m = new Mutation(prefix + ref.getRowSuffix());
         m.putDelete(ref.getServerAddress(), ref.getServerLockUUID());
         writer.addMutation(m);
       }
       log.debug("Deleted scan server file reference entries for files: {}", refsToDelete);
     } catch (MutationsRejectedException | TableNotFoundException e) {
       throw new RuntimeException(e);
     }
   }

 }
	/*
	* 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
	*
	* https://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.accumulo.server.metadata;

	import static java.nio.charset.StandardCharsets.UTF_8;
	import static org.apache.accumulo.core.metadata.RootTable.ZROOT_TABLET_GC_CANDIDATES;
	import static org.apache.accumulo.server.util.MetadataTableUtil.EMPTY_TEXT;

	import java.util.Collection;
	import java.util.Iterator;
	import java.util.Map;
	import java.util.Objects;
	import java.util.Set;
	import java.util.UUID;
	import java.util.function.Consumer;
	import java.util.stream.Collectors;
	import java.util.stream.Stream;
	import java.util.stream.StreamSupport;

	import org.apache.accumulo.core.client.BatchWriter;
	import org.apache.accumulo.core.client.IsolatedScanner;
	import org.apache.accumulo.core.client.MutationsRejectedException;
	import org.apache.accumulo.core.client.Scanner;
	import org.apache.accumulo.core.client.TableNotFoundException;
	import org.apache.accumulo.core.data.Key;
	import org.apache.accumulo.core.data.Mutation;
	import org.apache.accumulo.core.data.Range;
	import org.apache.accumulo.core.data.TableId;
	import org.apache.accumulo.core.data.Value;
	import org.apache.accumulo.core.dataImpl.KeyExtent;
	import org.apache.accumulo.core.fate.FateTxId;
	import org.apache.accumulo.core.gc.GcCandidate;
	import org.apache.accumulo.core.gc.ReferenceFile;
	import org.apache.accumulo.core.metadata.MetadataTable;
	import org.apache.accumulo.core.metadata.RootTable;
	import org.apache.accumulo.core.metadata.ScanServerRefTabletFile;
	import org.apache.accumulo.core.metadata.StoredTabletFile;
	import org.apache.accumulo.core.metadata.ValidationUtil;
	import org.apache.accumulo.core.metadata.schema.Ample;
	import org.apache.accumulo.core.metadata.schema.AmpleImpl;
	import org.apache.accumulo.core.metadata.schema.ExternalCompactionFinalState;
	import org.apache.accumulo.core.metadata.schema.ExternalCompactionId;
	import org.apache.accumulo.core.metadata.schema.MetadataSchema.BlipSection;
	import org.apache.accumulo.core.metadata.schema.MetadataSchema.DeletesSection;
	import org.apache.accumulo.core.metadata.schema.MetadataSchema.DeletesSection.SkewedKeyValue;
	import org.apache.accumulo.core.metadata.schema.MetadataSchema.ExternalCompactionSection;
	import org.apache.accumulo.core.metadata.schema.MetadataSchema.ScanServerFileReferenceSection;
	import org.apache.accumulo.core.metadata.schema.MetadataSchema.TabletsSection.BulkFileColumnFamily;
	import org.apache.accumulo.core.security.Authorizations;
	import org.apache.accumulo.server.ServerContext;
	import org.apache.hadoop.io.Text;
	import org.apache.zookeeper.KeeperException;
	import org.slf4j.Logger;
	import org.slf4j.LoggerFactory;

	import com.google.common.base.Preconditions;

	public class ServerAmpleImpl extends AmpleImpl implements Ample {

	private static Logger log = LoggerFactory.getLogger(ServerAmpleImpl.class);

	private ServerContext context;

	public ServerAmpleImpl(ServerContext context) {
	super(context);
	this.context = context;
	}

	@Override
	public Ample.TabletMutator mutateTablet(KeyExtent extent) {
	TabletsMutator tmi = mutateTablets();
	Ample.TabletMutator tabletMutator = tmi.mutateTablet(extent);
	((TabletMutatorBase) tabletMutator).setCloseAfterMutate(tmi);
	return tabletMutator;
	}

	@Override
	public TabletsMutator mutateTablets() {
	return new TabletsMutatorImpl(context);
	}

	private void mutateRootGcCandidates(Consumer<RootGcCandidates> mutator) {
	String zpath = context.getZooKeeperRoot() + ZROOT_TABLET_GC_CANDIDATES;
	try {
	context.getZooReaderWriter().mutateOrCreate(zpath, new byte[0], currVal -> {
	String currJson = new String(currVal, UTF_8);
	RootGcCandidates rgcc = new RootGcCandidates(currJson);
	log.debug("Root GC candidates before change : {}", currJson);
	mutator.accept(rgcc);
	String newJson = rgcc.toJson();
	log.debug("Root GC candidates after change : {}", newJson);
	if (newJson.length() > 262_144) {
	log.warn(
	"Root tablet deletion candidates stored in ZK at {} are getting large ({} bytes), is"
	+ " Accumulo GC process running? Large nodes may cause problems for Zookeeper!",
	zpath, newJson.length());
	}
	return newJson.getBytes(UTF_8);
	});
	} catch (Exception e) {
	throw new RuntimeException(e);
	}
	}

	@Override
	public void putGcCandidates(TableId tableId, Collection<StoredTabletFile> candidates) {

	if (RootTable.ID.equals(tableId)) {
	mutateRootGcCandidates(rgcc -> rgcc.add(candidates.stream()));
	return;
	}

	try (BatchWriter writer = context.createBatchWriter(DataLevel.of(tableId).metaTable())) {
	for (StoredTabletFile file : candidates) {
	writer.addMutation(createDeleteMutation(file));
	}
	} catch (MutationsRejectedException \| TableNotFoundException e) {
	throw new RuntimeException(e);
	}
	}

	@Override
	public void putGcFileAndDirCandidates(TableId tableId, Collection<ReferenceFile> candidates) {

	if (DataLevel.of(tableId) == DataLevel.ROOT) {
	// Directories are unexpected for the root tablet, so convert to stored tablet file
	mutateRootGcCandidates(rgcc -> rgcc.add(candidates.stream()
	.map(reference -> new StoredTabletFile(reference.getMetadataEntry()))));
	return;
	}

	try (BatchWriter writer = context.createBatchWriter(DataLevel.of(tableId).metaTable())) {
	for (var fileOrDir : candidates) {
	writer.addMutation(createDeleteMutation(fileOrDir));
	}
	} catch (MutationsRejectedException \| TableNotFoundException e) {
	throw new RuntimeException(e);
	}
	}

	@Override
	public void addBulkLoadInProgressFlag(String path, long fateTxid) {

	// Bulk Import operations are not supported on the metadata table, so no entries will ever be
	// required on the root table.
	Mutation m = new Mutation(BlipSection.getRowPrefix() + path);
	m.put(EMPTY_TEXT, EMPTY_TEXT, new Value(FateTxId.formatTid(fateTxid)));

	try (BatchWriter bw = context.createBatchWriter(MetadataTable.NAME)) {
	bw.addMutation(m);
	} catch (MutationsRejectedException \| TableNotFoundException e) {
	throw new RuntimeException(e);
	}
	}

	@Override
	public void removeBulkLoadInProgressFlag(String path) {

	// Bulk Import operations are not supported on the metadata table, so no entries will ever be
	// required on the root table.
	Mutation m = new Mutation(BlipSection.getRowPrefix() + path);
	m.putDelete(EMPTY_TEXT, EMPTY_TEXT);

	try (BatchWriter bw = context.createBatchWriter(MetadataTable.NAME)) {
	bw.addMutation(m);
	} catch (MutationsRejectedException \| TableNotFoundException e) {
	throw new RuntimeException(e);
	}
	}

	@Override
	public void removeBulkLoadEntries(TableId tableId, long tid, Text firstSplit, Text lastSplit) {
	Preconditions.checkArgument(DataLevel.of(tableId) == DataLevel.USER);
	try (
	Scanner mscanner =
	new IsolatedScanner(context.createScanner(MetadataTable.NAME, Authorizations.EMPTY));
	BatchWriter bw = context.createBatchWriter(MetadataTable.NAME)) {
	mscanner.setRange(new KeyExtent(tableId, lastSplit, firstSplit).toMetaRange());
	mscanner.fetchColumnFamily(BulkFileColumnFamily.NAME);

	for (Map.Entry<Key,Value> entry : mscanner) {
	log.trace("Looking at entry {} with tid {}", entry, tid);
	long entryTid = BulkFileColumnFamily.getBulkLoadTid(entry.getValue());
	if (tid == entryTid) {
	log.trace("deleting entry {}", entry);
	Key key = entry.getKey();
	Mutation m = new Mutation(key.getRow());
	m.putDelete(key.getColumnFamily(), key.getColumnQualifier());
	bw.addMutation(m);
	}
	}
	} catch (MutationsRejectedException \| TableNotFoundException e) {
	throw new RuntimeException(e);
	}
	}

	@Override
	public void deleteGcCandidates(DataLevel level, Collection<GcCandidate> candidates,
	GcCandidateType type) {

	if (level == DataLevel.ROOT) {
	if (type == GcCandidateType.INUSE) {
	// Since there is only a single root tablet, supporting INUSE candidate deletions would add
	// additional code complexity without any substantial benefit.
	// Therefore, deletion of root INUSE candidates is not supported.
	return;
	}
	mutateRootGcCandidates(rgcc -> rgcc.remove(candidates.stream()));
	return;
	}

	try (BatchWriter writer = context.createBatchWriter(level.metaTable())) {
	if (type == GcCandidateType.VALID) {
	for (GcCandidate candidate : candidates) {
	Mutation m = new Mutation(DeletesSection.encodeRow(candidate.getPath()));
	// Removes all versions of the candidate to avoid reprocessing deleted file entries
	m.putDelete(EMPTY_TEXT, EMPTY_TEXT);
	writer.addMutation(m);
	}
	} else {
	for (GcCandidate candidate : candidates) {
	Mutation m = new Mutation(DeletesSection.encodeRow(candidate.getPath()));
	// Removes this and older versions while allowing newer candidate versions to persist
	m.putDelete(EMPTY_TEXT, EMPTY_TEXT, candidate.getUid());
	writer.addMutation(m);
	}
	}
	} catch (MutationsRejectedException \| TableNotFoundException e) {
	throw new RuntimeException(e);
	}
	}

	@Override
	public Iterator<GcCandidate> getGcCandidates(DataLevel level) {
	if (level == DataLevel.ROOT) {
	var zooReader = context.getZooReader();
	byte[] jsonBytes;
	try {
	jsonBytes =
	zooReader.getData(context.getZooKeeperRoot() + RootTable.ZROOT_TABLET_GC_CANDIDATES);
	} catch (KeeperException \| InterruptedException e) {
	throw new RuntimeException(e);
	}
	return new RootGcCandidates(new String(jsonBytes, UTF_8)).sortedStream().iterator();
	} else if (level == DataLevel.METADATA \|\| level == DataLevel.USER) {
	Range range = DeletesSection.getRange();

	Scanner scanner;
	try {
	scanner = context.createScanner(level.metaTable(), Authorizations.EMPTY);
	} catch (TableNotFoundException e) {
	throw new RuntimeException(e);
	}
	scanner.setRange(range);
	return scanner.stream().filter(entry -> entry.getValue().equals(SkewedKeyValue.NAME))
	.map(
	entry -> new GcCandidate(DeletesSection.decodeRow(entry.getKey().getRow().toString()),
	entry.getKey().getTimestamp()))
	.iterator();
	} else {
	throw new IllegalArgumentException();
	}
	}

	@Override
	public Mutation createDeleteMutation(ReferenceFile tabletFilePathToRemove) {
	return createDelMutation(ValidationUtil.validate(tabletFilePathToRemove).getMetadataEntry());
	}

	public Mutation createDeleteMutation(StoredTabletFile pathToRemove) {
	return createDelMutation(pathToRemove.getMetaUpdateDelete());
	}

	private Mutation createDelMutation(String path) {
	Mutation delFlag = new Mutation(new Text(DeletesSection.encodeRow(path)));
	delFlag.put(EMPTY_TEXT, EMPTY_TEXT, DeletesSection.SkewedKeyValue.NAME);
	return delFlag;
	}

	@Override
	public void
	putExternalCompactionFinalStates(Collection<ExternalCompactionFinalState> finalStates) {
	try (BatchWriter writer = context.createBatchWriter(DataLevel.USER.metaTable())) {
	String prefix = ExternalCompactionSection.getRowPrefix();
	for (ExternalCompactionFinalState finalState : finalStates) {
	Mutation m = new Mutation(prefix + finalState.getExternalCompactionId().canonical());
	m.put("", "", finalState.toJson());
	writer.addMutation(m);
	}
	} catch (MutationsRejectedException \| TableNotFoundException e) {
	throw new RuntimeException(e);
	}
	}

	@Override
	public Stream<ExternalCompactionFinalState> getExternalCompactionFinalStates() {
	Scanner scanner;
	try {
	scanner = context.createScanner(DataLevel.USER.metaTable(), Authorizations.EMPTY);
	} catch (TableNotFoundException e) {
	throw new RuntimeException(e);
	}

	scanner.setRange(ExternalCompactionSection.getRange());
	int pLen = ExternalCompactionSection.getRowPrefix().length();
	return scanner.stream()
	.map(e -> ExternalCompactionFinalState.fromJson(
	ExternalCompactionId.of(e.getKey().getRowData().toString().substring(pLen)),
	e.getValue().toString()));
	}

	@Override
	public void
	deleteExternalCompactionFinalStates(Collection<ExternalCompactionId> statusesToDelete) {
	try (BatchWriter writer = context.createBatchWriter(DataLevel.USER.metaTable())) {
	String prefix = ExternalCompactionSection.getRowPrefix();
	for (ExternalCompactionId ecid : statusesToDelete) {
	Mutation m = new Mutation(prefix + ecid.canonical());
	m.putDelete(EMPTY_TEXT, EMPTY_TEXT);
	writer.addMutation(m);
	}
	log.debug("Deleted external compaction final state entries for external compactions: {}",
	statusesToDelete);
	} catch (MutationsRejectedException \| TableNotFoundException e) {
	throw new RuntimeException(e);
	}
	}

	@Override
	public void putScanServerFileReferences(Collection<ScanServerRefTabletFile> scanRefs) {
	try (BatchWriter writer = context.createBatchWriter(DataLevel.USER.metaTable())) {
	String prefix = ScanServerFileReferenceSection.getRowPrefix();
	for (ScanServerRefTabletFile ref : scanRefs) {
	Mutation m = new Mutation(prefix + ref.getRowSuffix());
	m.put(ref.getServerAddress(), ref.getServerLockUUID(), ref.getValue());
	writer.addMutation(m);
	}
	} catch (MutationsRejectedException \| TableNotFoundException e) {
	throw new IllegalStateException(
	"Error inserting scan server file references into " + DataLevel.USER.metaTable(), e);
	}
	}

	@Override
	public Stream<ScanServerRefTabletFile> getScanServerFileReferences() {
	try {
	Scanner scanner = context.createScanner(DataLevel.USER.metaTable(), Authorizations.EMPTY);
	scanner.setRange(ScanServerFileReferenceSection.getRange());
	int pLen = ScanServerFileReferenceSection.getRowPrefix().length();
	return StreamSupport.stream(scanner.spliterator(), false)
	.map(e -> new ScanServerRefTabletFile(e.getKey().getRowData().toString().substring(pLen),
	e.getKey().getColumnFamily(), e.getKey().getColumnQualifier()));
	} catch (TableNotFoundException e) {
	throw new IllegalStateException(DataLevel.USER.metaTable() + " not found!", e);
	}
	}

	@Override
	public void deleteScanServerFileReferences(String serverAddress, UUID scanServerLockUUID) {
	Objects.requireNonNull(serverAddress, "Server address must be supplied");
	Objects.requireNonNull(scanServerLockUUID, "Server uuid must be supplied");
	try (
	Scanner scanner = context.createScanner(DataLevel.USER.metaTable(), Authorizations.EMPTY)) {
	scanner.setRange(ScanServerFileReferenceSection.getRange());
	scanner.fetchColumn(new Text(serverAddress), new Text(scanServerLockUUID.toString()));

	int pLen = ScanServerFileReferenceSection.getRowPrefix().length();
	Set<ScanServerRefTabletFile> refsToDelete = StreamSupport.stream(scanner.spliterator(), false)
	.map(e -> new ScanServerRefTabletFile(e.getKey().getRowData().toString().substring(pLen),
	e.getKey().getColumnFamily(), e.getKey().getColumnQualifier()))
	.collect(Collectors.toSet());

	if (!refsToDelete.isEmpty()) {
	this.deleteScanServerFileReferences(refsToDelete);
	}
	} catch (TableNotFoundException e) {
	throw new IllegalStateException(DataLevel.USER.metaTable() + " not found!", e);
	}
	}

	@Override
	public void deleteScanServerFileReferences(Collection<ScanServerRefTabletFile> refsToDelete) {
	try (BatchWriter writer = context.createBatchWriter(DataLevel.USER.metaTable())) {
	String prefix = ScanServerFileReferenceSection.getRowPrefix();
	for (ScanServerRefTabletFile ref : refsToDelete) {
	Mutation m = new Mutation(prefix + ref.getRowSuffix());
	m.putDelete(ref.getServerAddress(), ref.getServerLockUUID());
	writer.addMutation(m);
	}
	log.debug("Deleted scan server file reference entries for files: {}", refsToDelete);
	} catch (MutationsRejectedException \| TableNotFoundException e) {
	throw new RuntimeException(e);
	}
	}

	}