sashapolo commented on a change in pull request #203: URL: https://github.com/apache/ignite-3/pull/203#discussion_r671065752
########## File path: modules/metastorage-server/src/main/java/org/apache/ignite/internal/metastorage/server/persistence/RocksDBKeyValueStorage.java ########## @@ -0,0 +1,1079 @@ +/* + * 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 + * + * http://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.ignite.internal.metastorage.server.persistence; + +import java.io.IOException; +import java.nio.ByteBuffer; +import java.nio.charset.StandardCharsets; +import java.nio.file.Files; +import java.nio.file.Path; +import java.nio.file.Paths; +import java.util.ArrayList; +import java.util.Arrays; +import java.util.Collection; +import java.util.Collections; +import java.util.Comparator; +import java.util.List; +import java.util.Map; +import java.util.NavigableMap; +import java.util.TreeMap; +import java.util.TreeSet; +import java.util.concurrent.CompletableFuture; +import java.util.concurrent.Executor; +import java.util.concurrent.Executors; +import java.util.concurrent.locks.ReadWriteLock; +import java.util.concurrent.locks.ReentrantReadWriteLock; +import org.apache.ignite.internal.metastorage.server.Condition; +import org.apache.ignite.internal.metastorage.server.Entry; +import org.apache.ignite.internal.metastorage.server.KeyValueStorage; +import org.apache.ignite.internal.metastorage.server.Operation; +import org.apache.ignite.internal.metastorage.server.Value; +import org.apache.ignite.internal.metastorage.server.WatchEvent; +import org.apache.ignite.internal.util.ByteUtils; +import org.apache.ignite.internal.util.Cursor; +import org.apache.ignite.internal.util.IgniteUtils; +import org.apache.ignite.lang.IgniteInternalException; +import org.jetbrains.annotations.NotNull; +import org.jetbrains.annotations.Nullable; +import org.jetbrains.annotations.TestOnly; +import org.rocksdb.EnvOptions; +import org.rocksdb.IngestExternalFileOptions; +import org.rocksdb.Options; +import org.rocksdb.ReadOptions; +import org.rocksdb.RocksDB; +import org.rocksdb.RocksDBException; +import org.rocksdb.RocksIterator; +import org.rocksdb.SstFileWriter; +import org.rocksdb.WriteBatch; +import org.rocksdb.WriteOptions; + +import static org.apache.ignite.internal.metastorage.server.Value.TOMBSTONE; + +/** + * Key-value storage based on RocksDB. + * Keys are stored with revision. + * Values are stored with update counter and a boolean flag which represents whether this record is a tombstone. + * <br> + * Key: [8 bytes revision, N bytes key itself]. + * <br> + * Value: [8 bytes update counter, 1 byte tombstone flag, N bytes value]. + */ +public class RocksDBKeyValueStorage implements KeyValueStorage { + /** Database snapshot file name. */ + private static final String SNAPSHOT_FILE_NAME = "db.snapshot"; + + /** Suffix for the temporary snapshot folder */ + private static final String TMP_SUFFIX = ".tmp"; + + // A revision to store with a system entries. + private static final long SYSTEM_REVISION_MARKER_VALUE = -1; + + /** Revision key. */ + private static final byte[] REVISION_KEY = keyToRocksKey( + SYSTEM_REVISION_MARKER_VALUE, + "SYSTEM_REVISION_KEY".getBytes(StandardCharsets.UTF_8) + ); + + /** Update counter key. */ + private static final byte[] UPDATE_COUNTER_KEY = keyToRocksKey( + SYSTEM_REVISION_MARKER_VALUE, + "SYSTEM_UPDATE_COUNTER_KEY".getBytes(StandardCharsets.UTF_8) + ); + + static { + RocksDB.loadLibrary(); + } + + /** RockDB options. */ + private final Options options; + + /** RocksDb instance. */ + private final RocksDB db; + + /** RW lock. */ + private final ReadWriteLock rwLock = new ReentrantReadWriteLock(); + + /** Thread-pool for snapshot operations execution. */ + private final Executor snapshotExecutor = Executors.newSingleThreadExecutor(); + + /** + * Special value for the revision number which means that operation should be applied + * to the latest revision of an entry. + */ + private static final long LATEST_REV = -1; + + /** Lexicographic order comparator. */ + static final Comparator<byte[]> CMP = Arrays::compare; + + /** Path to the rocksdb database. */ + private final Path dbPath; + + /** Keys index. Value is the list of all revisions under which the corresponding entry has ever been modified. */ + private NavigableMap<byte[], List<Long>> keysIdx = new TreeMap<>(CMP); + + /** Revision. Will be incremented for each single-entry or multi-entry update operation. */ + private long rev; + + /** Update counter. Will be incremented for each update of any particular entry. */ + private long updCntr; + + /** + * Constructor. + * + * @param dbPath RocksDB path. + */ + public RocksDBKeyValueStorage(Path dbPath) { + try { + options = new Options() + .setCreateIfMissing(true) + // The prefix is the revision of an entry, so prefix length is the size of a long + .useFixedLengthPrefixExtractor(Long.BYTES); + + this.dbPath = dbPath; + + this.db = RocksDB.open(options, dbPath.toAbsolutePath().toString()); + } + catch (Exception e) { + try { + close(); + } + catch (Exception exception) { + e.addSuppressed(exception); + } + + throw new IgniteInternalException("Failed to start the storage", e); + } + } + + /** {@inheritDoc} */ + @Override public void close() throws Exception { + IgniteUtils.closeAll(options, db); + } + + /** {@inheritDoc} */ + @Override public CompletableFuture<Void> snapshot(Path snapshotPath) { + Path tempPath = Paths.get(snapshotPath.toString() + TMP_SUFFIX); + + IgniteUtils.deleteIfExists(tempPath); + + try { + Files.createDirectories(tempPath); + } + catch (IOException e) { + return CompletableFuture.failedFuture( + new IgniteInternalException("Failed to create directory: " + tempPath, e) + ); + } + + return createSstFile(tempPath).thenAccept(aVoid -> { + IgniteUtils.deleteIfExists(snapshotPath); + + try { + Files.move(tempPath, snapshotPath); + } + catch (IOException e) { + throw new IgniteInternalException("Failed to rename: " + tempPath + " to " + snapshotPath, e); + } + }); + } + + /** {@inheritDoc} */ + @Override public void restoreSnapshot(Path path) { + Path snapshotPath = path.resolve(SNAPSHOT_FILE_NAME); + + if (!Files.exists(snapshotPath)) + throw new IgniteInternalException("Snapshot not found: " + snapshotPath); + + rwLock.writeLock().lock(); + + try (IngestExternalFileOptions ingestOptions = new IngestExternalFileOptions()) { + this.db.ingestExternalFile(Collections.singletonList(snapshotPath.toString()), ingestOptions); + buildKeyIndex(); + + rev = ByteUtils.bytesToLong(this.db.get(REVISION_KEY)); + + updCntr = ByteUtils.bytesToLong(this.db.get(UPDATE_COUNTER_KEY)); + } + catch (RocksDBException e) { + throw new IgniteInternalException("Fail to ingest sst file at path: " + path, e); + } + finally { + rwLock.writeLock().unlock(); + } + } + + /** + * Builds an index of this storage. + * + * @throws RocksDBException If failed. + */ + private void buildKeyIndex() throws RocksDBException { + try (RocksIterator iterator = this.db.newIterator()) { + for (iterator.seekToFirst(); iterator.isValid(); iterator.next()) { + byte[] rocksKey = iterator.key(); + + byte[] key = rocksKeyToBytes(rocksKey); + + long revision = ByteUtils.bytesToLong(rocksKey); + + if (revision == SYSTEM_REVISION_MARKER_VALUE) + // It's a system entry like REVISION_KEY, ignore it whily building key index. + continue; + + updateKeysIndex(key, revision); + } + + checkIterator(iterator); + } + } + + /** + * Creates a SST file from {@link #db}. + * + * @param path Path to store SST file at. + * @return Future that represents a state of the operation. + */ + private CompletableFuture<Void> createSstFile(Path path) { + return CompletableFuture.supplyAsync(() -> { + rwLock.readLock().lock(); + + try ( + ReadOptions readOptions = new ReadOptions(); + EnvOptions envOptions = new EnvOptions(); + Options options = new Options(); + RocksIterator it = this.db.newIterator(readOptions); + SstFileWriter sstFileWriter = new SstFileWriter(envOptions, options) + ) { + Path sstFile = path.resolve(SNAPSHOT_FILE_NAME); + + sstFileWriter.open(sstFile.toString()); + + for (it.seekToFirst(); it.isValid(); it.next()) + sstFileWriter.put(it.key(), it.value()); + + checkIterator(it); + + sstFileWriter.finish(); Review comment: cool! -- This is an automated message from the Apache Git Service. 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