public static void initOptions()

in hugegraph-store/hg-store-rocksdb/src/main/java/org/apache/hugegraph/rocksdb/access/RocksDBSession.java [128:264]
106 lines of code
12 McCabe index (conditional complexity)

    public static void initOptions(HugeConfig conf,
                                   DBOptionsInterface<?> db,
                                   MutableDBOptionsInterface<?> mdb,
                                   ColumnFamilyOptionsInterface<?> cf,
                                   MutableColumnFamilyOptionsInterface<?> mcf) {
        final boolean optimize = conf.get(RocksDBOptions.OPTIMIZE_MODE);
        if (db != null) {
            /*
             * Set true then the database will be created if it is missing.
             * should we use options.setCreateMissingColumnFamilies()?
             */
            db.setCreateIfMissing(true);
            if (optimize) {
                int processors = RocksDBSession.CPUS;
                db.setIncreaseParallelism(Math.max(processors / 2, 1));
                db.setAllowConcurrentMemtableWrite(true);
                db.setEnableWriteThreadAdaptiveYield(true);
            }
            db.setInfoLogLevel(
                    RocksDBOptions.LOG_LEVEL_MAPPING.get(conf.get(RocksDBOptions.LOG_LEVEL)));
            db.setMaxSubcompactions(conf.get(RocksDBOptions.MAX_SUB_COMPACTIONS));
            db.setAllowMmapWrites(conf.get(RocksDBOptions.ALLOW_MMAP_WRITES));
            db.setAllowMmapReads(conf.get(RocksDBOptions.ALLOW_MMAP_READS));
            db.setUseDirectReads(conf.get(RocksDBOptions.USE_DIRECT_READS));
            db.setUseDirectIoForFlushAndCompaction(
                    conf.get(RocksDBOptions.USE_DIRECT_READS_WRITES_FC));
            db.setMaxManifestFileSize(conf.get(RocksDBOptions.MAX_MANIFEST_FILE_SIZE));
            db.setSkipStatsUpdateOnDbOpen(conf.get(RocksDBOptions.SKIP_STATS_UPDATE_ON_DB_OPEN));
            db.setMaxFileOpeningThreads(conf.get(RocksDBOptions.MAX_FILE_OPENING_THREADS));
            db.setDbWriteBufferSize(conf.get(RocksDBOptions.DB_MEMTABLE_SIZE));
            WriteBufferManager bufferManager =
                    (WriteBufferManager) conf.getProperty(RocksDBOptions.WRITE_BUFFER_MANAGER);
            if (bufferManager != null) {
                db.setWriteBufferManager(bufferManager);
                log.info("rocksdb use global WriteBufferManager");
            }
            Env env = (Env) conf.getProperty(RocksDBOptions.ENV);
            if (env != null) {
                db.setEnv(env);
            }
        }

        if (mdb != null) {
            /*
             * Migrate to max_background_jobs option
             * https://github.com/facebook/rocksdb/wiki/Thread-Pool
             * https://github.com/facebook/rocksdb/pull/2205/files
             */
            mdb.setMaxBackgroundJobs(conf.get(RocksDBOptions.MAX_BG_JOBS));
            mdb.setDelayedWriteRate(conf.get(RocksDBOptions.DELAYED_WRITE_RATE));
            mdb.setMaxOpenFiles(conf.get(RocksDBOptions.MAX_OPEN_FILES));
            mdb.setMaxTotalWalSize(conf.get(RocksDBOptions.MAX_TOTAL_WAL_SIZE));
            mdb.setDeleteObsoleteFilesPeriodMicros(
                    1000000 * conf.get(RocksDBOptions.DELETE_OBSOLETE_FILE_PERIOD));
        }

        if (cf != null) {
            if (optimize) {
                // Optimize RocksDB
                cf.optimizeLevelStyleCompaction();
                cf.optimizeUniversalStyleCompaction();
            }

            int numLevels = conf.get(RocksDBOptions.NUM_LEVELS);
            List<CompressionType> compressions = conf.get(
                    RocksDBOptions.LEVELS_COMPRESSIONS);
            E.checkArgument(compressions.isEmpty() ||
                            compressions.size() == numLevels,
                            "Elements number of '%s' must be 0 or " +
                            "be the same as '%s', but got %s != %s",
                            RocksDBOptions.LEVELS_COMPRESSIONS.name(),
                            RocksDBOptions.NUM_LEVELS.name(),
                            compressions.size(), numLevels);

            cf.setNumLevels(numLevels);
            cf.setCompactionStyle(conf.get(RocksDBOptions.COMPACTION_STYLE));

            cf.setBottommostCompressionType(
                    conf.get(RocksDBOptions.BOTTOMMOST_COMPRESSION));
            if (!compressions.isEmpty()) {
                cf.setCompressionPerLevel(compressions);
            }

            cf.setMinWriteBufferNumberToMerge(
                    conf.get(RocksDBOptions.MIN_MEMTABLES_TO_MERGE));
            cf.setMaxWriteBufferNumberToMaintain(
                    conf.get(RocksDBOptions.MAX_MEMTABLES_TO_MAINTAIN));

            cf.setLevelCompactionDynamicLevelBytes(
                    conf.get(RocksDBOptions.DYNAMIC_LEVEL_BYTES));

            // https://github.com/facebook/rocksdb/wiki/Block-Cache
            BlockBasedTableConfig tableConfig =
                    (BlockBasedTableConfig) conf.getProperty(RocksDBOptions.BLOCK_TABLE_CONFIG);

            if (tableConfig != null) {
                cf.setTableFormatConfig(tableConfig);
            }

            cf.setOptimizeFiltersForHits(
                    conf.get(RocksDBOptions.BLOOM_FILTERS_SKIP_LAST_LEVEL));

            // https://github.com/facebook/rocksdb/tree/master/utilities/merge_operators
            cf.setMergeOperatorName("uint64add"); // uint64add/stringappend
        }

        if (mcf != null) {
            mcf.setCompressionType(conf.get(RocksDBOptions.COMPRESSION));

            mcf.setWriteBufferSize(conf.get(RocksDBOptions.MEMTABLE_SIZE));
            mcf.setMaxWriteBufferNumber(conf.get(RocksDBOptions.MAX_MEMTABLES));

            mcf.setMaxBytesForLevelBase(
                    conf.get(RocksDBOptions.MAX_LEVEL1_BYTES));
            mcf.setMaxBytesForLevelMultiplier(
                    conf.get(RocksDBOptions.MAX_LEVEL_BYTES_MULTIPLIER));

            mcf.setTargetFileSizeBase(
                    conf.get(RocksDBOptions.TARGET_FILE_SIZE_BASE));
            mcf.setTargetFileSizeMultiplier(
                    conf.get(RocksDBOptions.TARGET_FILE_SIZE_MULTIPLIER));

            mcf.setLevel0FileNumCompactionTrigger(
                    conf.get(RocksDBOptions.LEVEL0_COMPACTION_TRIGGER));
            mcf.setLevel0SlowdownWritesTrigger(
                    conf.get(RocksDBOptions.LEVEL0_SLOWDOWN_WRITES_TRIGGER));
            mcf.setLevel0StopWritesTrigger(
                    conf.get(RocksDBOptions.LEVEL0_STOP_WRITES_TRIGGER));

            mcf.setSoftPendingCompactionBytesLimit(
                    conf.get(RocksDBOptions.SOFT_PENDING_COMPACTION_LIMIT));
            mcf.setHardPendingCompactionBytesLimit(
                    conf.get(RocksDBOptions.HARD_PENDING_COMPACTION_LIMIT));

            // conf.get(RocksDBOptions.BULKLOAD_MODE);
        }
    }