Unverified Commit a7707ff5 authored by Tommaso Tocci's avatar Tommaso Tocci
Browse files

Remove unused config constant regarding RocksDB

parent f20c2710
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+1 −5
Original line number Diff line number Diff line
@@ -33,11 +33,7 @@
//#define ZERO_BUFFER_BEFORE_READ

// Write-ahead logging of rocksdb
//#define KV_WOL
// Optimize Key-Value store. Eventually, different modes will be available for different workloads. TODO
//#define KV_OPTIMIZE
// Optimize Key-Value store for tmpfs/ramdisk usage
//#define KV_OPTIMIZE_RAMDISK
#define KV_WOL false

// Buffer size for Rocksdb. A high number means that all entries are held in memory.
// However, when full the application blocks until **all** entries are flushed to disk.
+1 −46
Original line number Diff line number Diff line
@@ -16,10 +16,7 @@ MetadataDB::MetadataDB(const std::string& path): path(path) {
    options.create_if_missing = true;
    options.merge_operator.reset(new MetadataMergeOperator);
    MetadataDB::optimize_rocksdb_options(options);

#if !defined(KV_WOL)
    write_opts.disableWAL = true;
#endif
    write_opts.disableWAL = !(KV_WOL);
    rdb::DB * rdb_ptr;
    auto s = rocksdb::DB::Open(options, path, &rdb_ptr);
    if (!s.ok()) {
@@ -179,48 +176,6 @@ void MetadataDB::iterate_all() {
void MetadataDB::optimize_rocksdb_options(rdb::Options& options) {
    options.max_successive_merges = 128;

#if defined(KV_OPTIMIZE_RAMDISK)
    // as described at https://github.com/facebook/rocksdb/wiki/RocksDB-Tuning-Guide
    // use mmap read
    options.allow_mmap_reads = true;
    // disable block cache, enable blook filters and reduce the delta encoding restart interval
    rocksdb::BlockBasedTableOptions table_options{};
    table_options.filter_policy.reset(rocksdb::NewBloomFilterPolicy(10, true));
    table_options.no_block_cache = true;
    table_options.block_restart_interval = 4;
    options.table_factory.reset(NewBlockBasedTableFactory(table_options));
    // enable lightweight compression (snappy or lz4). We use lz4 for now
    options.compression = rocksdb::CompressionType::kLZ4Compression;
    // set up compression more aggressively and allocate more threads for flush and compaction
    options.level0_file_num_compaction_trigger = 1;
    options.max_background_flushes = 8;
    options.max_background_compactions = 8;
    options.max_subcompactions = 4;
    // keep all the files open
    options.max_open_files = -1;
#elif defined(KV_OPTIMIZE)
    // rocksdb::BlockBasedTableOptions block_options{};
    // block_options.block_size = 16384 * 2;
    // options.table_factory.reset(rocksdb::NewBlockBasedTableFactory(block_options));
    // experimental settings
    // options.write_buffer_size = 512;
    // options.max_write_buffer_number = 16;
    // options.min_write_buffer_number_to_merge = 4;
    // These 4 below have the most impact
    options.max_bytes_for_level_base = 2048;
    options.max_bytes_for_level_multiplier = 10;
    options.target_file_size_base = 256;
    options.target_file_size_multiplier = 1;

    options.max_background_flushes = 1;
    options.max_background_compactions = 48;
    options.level0_file_num_compaction_trigger = 1;
    options.level0_slowdown_writes_trigger = 48;
    options.level0_stop_writes_trigger = 56;
    // options.arena_block_size = 1024 * 8;
    // options.compression = rocksdb::kNoCompression; // doesnt do anything
#endif

#if defined(KV_WRITE_BUFFER)
    // write_buffer_size is multiplied by the write_buffer_number to get the amount of data hold in memory.
    // at min_write_buffer_number_to_merge rocksdb starts to flush entries out to disk