SammyVimes commented on a change in pull request #203: URL: https://github.com/apache/ignite-3/pull/203#discussion_r673129308
########## File path: modules/metastorage-server/src/main/java/org/apache/ignite/internal/metastorage/server/persistence/RocksDBKeyValueStorage.java ########## @@ -0,0 +1,1093 @@ +/* + * 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.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.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 java.util.stream.Collectors; +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.Cursor; +import org.apache.ignite.internal.util.IgniteUtils; +import org.apache.ignite.lang.IgniteBiTuple; +import org.apache.ignite.lang.IgniteInternalException; +import org.jetbrains.annotations.NotNull; +import org.jetbrains.annotations.Nullable; +import org.jetbrains.annotations.TestOnly; +import org.rocksdb.ColumnFamilyDescriptor; +import org.rocksdb.ColumnFamilyHandle; +import org.rocksdb.ColumnFamilyOptions; +import org.rocksdb.DBOptions; +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.Snapshot; +import org.rocksdb.SstFileWriter; +import org.rocksdb.WriteBatch; +import org.rocksdb.WriteOptions; + +import static org.apache.ignite.internal.metastorage.server.Value.TOMBSTONE; +import static org.apache.ignite.internal.metastorage.server.persistence.RocksStorageUtils.addLongToLongsByteArray; +import static org.apache.ignite.internal.metastorage.server.persistence.RocksStorageUtils.bytesToLong; +import static org.apache.ignite.internal.metastorage.server.persistence.RocksStorageUtils.bytesToValue; +import static org.apache.ignite.internal.metastorage.server.persistence.RocksStorageUtils.find; +import static org.apache.ignite.internal.metastorage.server.persistence.RocksStorageUtils.forEach; +import static org.apache.ignite.internal.metastorage.server.persistence.RocksStorageUtils.getAsLongs; +import static org.apache.ignite.internal.metastorage.server.persistence.RocksStorageUtils.keyToRocksKey; +import static org.apache.ignite.internal.metastorage.server.persistence.RocksStorageUtils.longToBytes; +import static org.apache.ignite.internal.metastorage.server.persistence.RocksStorageUtils.valueToBytes; +import static org.apache.ignite.internal.metastorage.server.persistence.StorageColumnFamilyType.DATA; +import static org.apache.ignite.internal.metastorage.server.persistence.StorageColumnFamilyType.INDEX; + +/** + * Key-value storage based on RocksDB. + * Keys are stored with revision. + * Values are stored with an 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 { + /** Suffix for the temporary snapshot folder */ + private static final String TMP_SUFFIX = ".tmp"; + + /** A revision to store with 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 DBOptions options; + + /** RocksDb instance. */ + private final RocksDB db; + + /** Data column family. */ + private final ColumnFamily data; + + /** Index column family. */ + private final ColumnFamily index; + + /** RW lock. */ + private final ReadWriteLock rwLock = new ReentrantReadWriteLock(); + + /** Thread-pool for snapshot operations execution. */ + private final Executor snapshotExecutor = Executors.newFixedThreadPool(2); + + /** + * 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; + + /** 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 DBOptions() + .setCreateMissingColumnFamilies(true) + .setCreateIfMissing(true); + + this.dbPath = dbPath; + + Options dataOptions = new Options().setCreateIfMissing(true) + // The prefix is the revision of an entry, so prefix length is the size of a long + .useFixedLengthPrefixExtractor(Long.BYTES); + + ColumnFamilyOptions dataFamilyOptions = new ColumnFamilyOptions(dataOptions); + + Options indexOptions = new Options().setCreateIfMissing(true); + + ColumnFamilyOptions indexFamilyOptions = new ColumnFamilyOptions(indexOptions); + + List<ColumnFamilyDescriptor> descriptors = Arrays.asList( + new ColumnFamilyDescriptor(DATA.nameAsBytes(), dataFamilyOptions), + new ColumnFamilyDescriptor(INDEX.nameAsBytes(), indexFamilyOptions) + ); + + var handles = new ArrayList<ColumnFamilyHandle>(); + + // Delete existing data, relying on the raft's snapshot and log playback + destroyRocksDB(); + + this.db = RocksDB.open(options, dbPath.toAbsolutePath().toString(), descriptors, handles); + + data = new ColumnFamily(db, handles.get(0), DATA, dataFamilyOptions, dataOptions); + + index = new ColumnFamily(db, handles.get(1), INDEX, indexFamilyOptions, indexOptions); + } + catch (Exception e) { + try { + close(); + } + catch (Exception exception) { + e.addSuppressed(exception); + } + + throw new IgniteInternalException("Failed to start the storage", e); + } + } + + /** + * Clear the RocksDB instance. + * The major difference with directly deleting the DB directory manually is that + * destroyDB() will take care of the case where the RocksDB database is stored + * in multiple directories. For instance, a single DB can be configured to store + * its data in multiple directories by specifying different paths to + * DBOptions::db_paths, DBOptions::db_log_dir, and DBOptions::wal_dir. + * + * @throws RocksDBException If failed. + */ + private void destroyRocksDB() throws RocksDBException { + try (final Options opt = new Options()) { + RocksDB.destroyDB(dbPath.toString(), opt); + } + } + + /** {@inheritDoc} */ + @Override public void close() throws Exception { + IgniteUtils.closeAll(options, data, index, db); + } + + /** {@inheritDoc} */ + @NotNull + @Override public CompletableFuture<Void> snapshot(Path snapshotPath) { Review comment: Nothing bad at all, we'll just use the snapshot of the database at the time when a snapshot was requested. I'm not sure though that this situation won't happen, but afaik it should not. -- This is an automated message from the Apache Git Service. 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