321dfdc3ae
Summary: The leveldb API is enhanced to support different compression algorithms at different levels. This adds the option min_level_to_compress to db_bench that specifies the minimum level for which compression should be done when compression is enabled. This can be used to disable compression for levels 0 and 1 which are likely to suffer from stalls because of the CPU load for memtable flushes and (L0,L1) compaction. Level 0 is special as it gets frequent memtable flushes. Level 1 is special as it frequently gets all:all file compactions between it and level 0. But all other levels could be the same. For any level N where N > 1, the rate of sequential IO for that level should be the same. The last level is the exception because it might not be full and because files from it are not read to compact with the next larger level. The same amount of time will be spent doing compaction at any level N excluding N=0, 1 or the last level. By this standard all of those levels should use the same compression. The difference is that the loss (using more disk space) from a faster compression algorithm is less significant for N=2 than for N=3. So we might be willing to trade disk space for faster write rates with no compression for L0 and L1, snappy for L2, zlib for L3. Using a faster compression algorithm for the mid levels also allows us to reclaim some cpu without trading off much loss in disk space overhead. Also note that little is to be gained by compressing levels 0 and 1. For a 4-level tree they account for 10% of the data. For a 5-level tree they account for 1% of the data. With compression enabled: * memtable flush rate is ~18MB/second * (L0,L1) compaction rate is ~30MB/second With compression enabled but min_level_to_compress=2 * memtable flush rate is ~320MB/second * (L0,L1) compaction rate is ~560MB/second This practicaly takes the same code from https://reviews.facebook.net/D6225 but makes the leveldb api more general purpose with a few additional lines of code. Test Plan: make check Differential Revision: https://reviews.facebook.net/D6261
1805 lines
55 KiB
C++
1805 lines
55 KiB
C++
// Copyright (c) 2011 The LevelDB Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style license that can be
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// found in the LICENSE file. See the AUTHORS file for names of contributors.
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#include "db/db_impl.h"
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#include <algorithm>
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#include <set>
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#include <string>
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#include <stdint.h>
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#include <stdio.h>
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#include <vector>
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#include <algorithm>
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#include "db/builder.h"
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#include "db/db_iter.h"
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#include "db/dbformat.h"
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#include "db/filename.h"
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#include "db/log_reader.h"
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#include "db/log_writer.h"
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#include "db/memtable.h"
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#include "db/table_cache.h"
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#include "db/version_set.h"
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#include "db/write_batch_internal.h"
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#include "leveldb/db.h"
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#include "leveldb/env.h"
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#include "leveldb/status.h"
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#include "leveldb/table.h"
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#include "leveldb/table_builder.h"
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#include "port/port.h"
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#include "table/block.h"
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#include "table/merger.h"
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#include "table/two_level_iterator.h"
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#include "util/coding.h"
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#include "util/logging.h"
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#include "util/mutexlock.h"
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#include "util/build_version.h"
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#include "util/auto_split_logger.h"
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namespace leveldb {
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void dumpLeveldbBuildVersion(Logger * log);
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static Status NewLogger(const std::string& dbname,
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const std::string& db_log_dir,
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Env* env,
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size_t max_log_file_size,
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Logger** logger) {
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std::string db_absolute_path;
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env->GetAbsolutePath(dbname, &db_absolute_path);
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if (max_log_file_size > 0) { // need to auto split the log file?
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AutoSplitLogger<Logger>* auto_split_logger =
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new AutoSplitLogger<Logger>(env, dbname, db_log_dir, max_log_file_size);
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Status s = auto_split_logger->GetStatus();
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if (!s.ok()) {
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delete auto_split_logger;
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} else {
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*logger = auto_split_logger;
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}
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return s;
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} else {
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// Open a log file in the same directory as the db
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env->CreateDir(dbname); // In case it does not exist
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std::string fname = InfoLogFileName(dbname, db_absolute_path, db_log_dir);
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env->RenameFile(fname, OldInfoLogFileName(dbname, env->NowMicros(),
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db_absolute_path, db_log_dir));
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return env->NewLogger(fname, logger);
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}
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}
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// Information kept for every waiting writer
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struct DBImpl::Writer {
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Status status;
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WriteBatch* batch;
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bool sync;
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bool disableWAL;
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bool done;
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port::CondVar cv;
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explicit Writer(port::Mutex* mu) : cv(mu) { }
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};
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struct DBImpl::CompactionState {
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Compaction* const compaction;
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// Sequence numbers < smallest_snapshot are not significant since we
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// will never have to service a snapshot below smallest_snapshot.
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// Therefore if we have seen a sequence number S <= smallest_snapshot,
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// we can drop all entries for the same key with sequence numbers < S.
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SequenceNumber smallest_snapshot;
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// Files produced by compaction
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struct Output {
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uint64_t number;
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uint64_t file_size;
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InternalKey smallest, largest;
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};
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std::vector<Output> outputs;
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// State kept for output being generated
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WritableFile* outfile;
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TableBuilder* builder;
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uint64_t total_bytes;
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Output* current_output() { return &outputs[outputs.size()-1]; }
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explicit CompactionState(Compaction* c)
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: compaction(c),
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outfile(NULL),
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builder(NULL),
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total_bytes(0) {
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}
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};
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struct DBImpl::DeletionState {
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// the set of all live files that cannot be deleted
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std::set<uint64_t> live;
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// a list of all siles that exists in the db directory
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std::vector<std::string> allfiles;
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// the current filenumber, lognumber and prevlognumber
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// that corresponds to the set of files in 'live'.
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uint64_t filenumber, lognumber, prevlognumber;
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// the list of all files to be evicted from the table cahce
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std::vector<uint64_t> files_to_evict;
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};
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// Fix user-supplied options to be reasonable
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template <class T,class V>
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static void ClipToRange(T* ptr, V minvalue, V maxvalue) {
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if (static_cast<V>(*ptr) > maxvalue) *ptr = maxvalue;
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if (static_cast<V>(*ptr) < minvalue) *ptr = minvalue;
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}
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Options SanitizeOptions(const std::string& dbname,
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const InternalKeyComparator* icmp,
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const InternalFilterPolicy* ipolicy,
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const Options& src) {
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Options result = src;
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result.comparator = icmp;
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result.filter_policy = (src.filter_policy != NULL) ? ipolicy : NULL;
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ClipToRange(&result.max_open_files, 20, 50000);
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ClipToRange(&result.write_buffer_size, 64<<10, 1<<30);
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ClipToRange(&result.block_size, 1<<10, 4<<20);
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if (result.info_log == NULL) {
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Status s = NewLogger(dbname, result.db_log_dir, src.env,
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result.max_log_file_size, &result.info_log);
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if (!s.ok()) {
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// No place suitable for logging
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result.info_log = NULL;
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}
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}
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if (result.block_cache == NULL) {
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result.block_cache = NewLRUCache(8 << 20);
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}
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if (src.compression_per_level != NULL) {
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result.compression_per_level = new CompressionType[src.num_levels];
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for (unsigned int i = 0; i < src.num_levels; i++) {
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result.compression_per_level[i] = src.compression_per_level[i];
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}
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}
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return result;
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}
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DBImpl::DBImpl(const Options& options, const std::string& dbname)
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: env_(options.env),
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internal_comparator_(options.comparator),
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internal_filter_policy_(options.filter_policy),
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options_(SanitizeOptions(
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dbname, &internal_comparator_, &internal_filter_policy_, options)),
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owns_info_log_(options_.info_log != options.info_log),
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owns_cache_(options_.block_cache != options.block_cache),
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dbname_(dbname),
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db_lock_(NULL),
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shutting_down_(NULL),
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bg_cv_(&mutex_),
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mem_(new MemTable(internal_comparator_)),
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imm_(NULL),
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logfile_(NULL),
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logfile_number_(0),
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log_(NULL),
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tmp_batch_(new WriteBatch),
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bg_compaction_scheduled_(false),
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bg_logstats_scheduled_(false),
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manual_compaction_(NULL),
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logger_(NULL),
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disable_delete_obsolete_files_(false),
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delete_obsolete_files_last_run_(0),
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stall_level0_slowdown_(0),
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stall_leveln_slowdown_(0),
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stall_memtable_compaction_(0),
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stall_level0_num_files_(0),
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started_at_(options.env->NowMicros()) {
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mem_->Ref();
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has_imm_.Release_Store(NULL);
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env_->GetAbsolutePath(dbname, &db_absolute_path_);
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stats_ = new CompactionStats[options.num_levels];
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// Reserve ten files or so for other uses and give the rest to TableCache.
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const int table_cache_size = options_.max_open_files - 10;
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table_cache_ = new TableCache(dbname_, &options_, table_cache_size);
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versions_ = new VersionSet(dbname_, &options_, table_cache_,
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&internal_comparator_);
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dumpLeveldbBuildVersion(options_.info_log);
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options_.Dump(options_.info_log);
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#ifdef USE_SCRIBE
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logger_ = new ScribeLogger("localhost", 1456);
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#endif
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char name[100];
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Status st = env_->GetHostName(name, 100L);
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if(st.ok()) {
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host_name_ = name;
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} else {
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Log(options_.info_log, "Can't get hostname, use localhost as host name.");
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host_name_ = "localhost";
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}
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last_log_ts = 0;
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}
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DBImpl::~DBImpl() {
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// Wait for background work to finish
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mutex_.Lock();
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shutting_down_.Release_Store(this); // Any non-NULL value is ok
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while (bg_compaction_scheduled_ || bg_logstats_scheduled_) {
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bg_cv_.Wait();
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}
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mutex_.Unlock();
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if (db_lock_ != NULL) {
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env_->UnlockFile(db_lock_);
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}
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delete versions_;
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if (mem_ != NULL) mem_->Unref();
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if (imm_ != NULL) imm_->Unref();
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delete tmp_batch_;
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delete log_;
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delete logfile_;
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delete table_cache_;
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delete[] stats_;
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if (owns_info_log_) {
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delete options_.info_log;
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}
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if (owns_cache_) {
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delete options_.block_cache;
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}
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if (options_.compression_per_level != NULL) {
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delete options_.compression_per_level;
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}
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delete logger_;
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}
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Status DBImpl::NewDB() {
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VersionEdit new_db(NumberLevels());
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new_db.SetComparatorName(user_comparator()->Name());
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new_db.SetLogNumber(0);
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new_db.SetNextFile(2);
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new_db.SetLastSequence(0);
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const std::string manifest = DescriptorFileName(dbname_, 1);
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WritableFile* file;
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Status s = env_->NewWritableFile(manifest, &file);
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if (!s.ok()) {
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return s;
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}
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{
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log::Writer log(file);
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std::string record;
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new_db.EncodeTo(&record);
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s = log.AddRecord(record);
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if (s.ok()) {
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s = file->Close();
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}
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}
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delete file;
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if (s.ok()) {
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// Make "CURRENT" file that points to the new manifest file.
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s = SetCurrentFile(env_, dbname_, 1);
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} else {
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env_->DeleteFile(manifest);
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}
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return s;
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}
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void DBImpl::MaybeIgnoreError(Status* s) const {
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if (s->ok() || options_.paranoid_checks) {
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// No change needed
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} else {
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Log(options_.info_log, "Ignoring error %s", s->ToString().c_str());
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*s = Status::OK();
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}
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}
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// Returns the list of live files in 'live' and the list
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// of all files in the filesystem in 'allfiles'.
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void DBImpl::FindObsoleteFiles(DeletionState& deletion_state) {
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mutex_.AssertHeld();
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// if deletion is disabled, do nothing
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if (disable_delete_obsolete_files_) {
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return;
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}
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// This method is costly when the number of files is large.
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// Do not allow it to trigger more often than once in
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// delete_obsolete_files_period_micros.
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if (options_.delete_obsolete_files_period_micros != 0) {
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const uint64_t now_micros = env_->NowMicros();
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if (delete_obsolete_files_last_run_ +
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options_.delete_obsolete_files_period_micros > now_micros) {
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return;
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}
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delete_obsolete_files_last_run_ = now_micros;
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}
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// Make a set of all of the live files
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deletion_state.live = pending_outputs_;
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versions_->AddLiveFiles(&deletion_state.live);
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// set of all files in the directory
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env_->GetChildren(dbname_, &deletion_state.allfiles); // Ignore errors
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// store the current filenum, lognum, etc
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deletion_state.filenumber = versions_->ManifestFileNumber();
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deletion_state.lognumber = versions_->LogNumber();
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deletion_state.prevlognumber = versions_->PrevLogNumber();
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}
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// Diffs the files listed in filenames and those that do not
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// belong to live files are posibly removed. If the removed file
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// is a sst file, then it returns the file number in files_to_evict.
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// It is not necesary to hold the mutex when invoking this method.
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void DBImpl::PurgeObsoleteFiles(DeletionState& state) {
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uint64_t number;
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FileType type;
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std::vector<std::string> old_log_files;
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for (size_t i = 0; i < state.allfiles.size(); i++) {
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if (ParseFileName(state.allfiles[i], &number, &type)) {
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bool keep = true;
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switch (type) {
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case kLogFile:
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keep = ((number >= state.lognumber) ||
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(number == state.prevlognumber));
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break;
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case kDescriptorFile:
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// Keep my manifest file, and any newer incarnations'
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// (in case there is a race that allows other incarnations)
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keep = (number >= state.filenumber);
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break;
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case kTableFile:
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keep = (state.live.find(number) != state.live.end());
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break;
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case kTempFile:
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// Any temp files that are currently being written to must
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// be recorded in pending_outputs_, which is inserted into "live"
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keep = (state.live.find(number) != state.live.end());
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break;
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case kInfoLogFile:
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keep = true;
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if (number != 0) {
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old_log_files.push_back(state.allfiles[i]);
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}
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break;
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case kCurrentFile:
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case kDBLockFile:
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keep = true;
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break;
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}
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if (!keep) {
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if (type == kTableFile) {
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// record the files to be evicted from the cache
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state.files_to_evict.push_back(number);
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}
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Log(options_.info_log, "Delete type=%d #%lld\n",
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int(type),
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static_cast<unsigned long long>(number));
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Status st = env_->DeleteFile(dbname_ + "/" + state.allfiles[i]);
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if(!st.ok()) {
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Log(options_.info_log, "Delete type=%d #%lld FAILED\n",
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int(type),
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static_cast<unsigned long long>(number));
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}
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}
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}
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}
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// Delete old log files.
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int old_log_file_count = old_log_files.size();
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if (old_log_file_count >= KEEP_LOG_FILE_NUM &&
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!options_.db_log_dir.empty()) {
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std::sort(old_log_files.begin(), old_log_files.end());
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for (int i = 0; i >= (old_log_file_count - KEEP_LOG_FILE_NUM); i++) {
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std::string& to_delete = old_log_files.at(i);
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Log(options_.info_log, "Delete type=%d %s\n",
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int(kInfoLogFile), to_delete.c_str());
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env_->DeleteFile(dbname_ + "/" + to_delete);
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}
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}
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}
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void DBImpl::EvictObsoleteFiles(DeletionState& state) {
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mutex_.AssertHeld();
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for (unsigned int i = 0; i < state.files_to_evict.size(); i++) {
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table_cache_->Evict(state.files_to_evict[i]);
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}
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}
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void DBImpl::DeleteObsoleteFiles() {
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mutex_.AssertHeld();
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DeletionState deletion_state;
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std::set<uint64_t> live;
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std::vector<std::string> allfiles;
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std::vector<uint64_t> files_to_evict;
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uint64_t filenumber, lognumber, prevlognumber;
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FindObsoleteFiles(deletion_state);
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PurgeObsoleteFiles(deletion_state);
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EvictObsoleteFiles(deletion_state);
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}
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Status DBImpl::Recover(VersionEdit* edit) {
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mutex_.AssertHeld();
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// Ignore error from CreateDir since the creation of the DB is
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// committed only when the descriptor is created, and this directory
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// may already exist from a previous failed creation attempt.
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env_->CreateDir(dbname_);
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assert(db_lock_ == NULL);
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Status s = env_->LockFile(LockFileName(dbname_), &db_lock_);
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if (!s.ok()) {
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return s;
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}
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if (!env_->FileExists(CurrentFileName(dbname_))) {
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if (options_.create_if_missing) {
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s = NewDB();
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if (!s.ok()) {
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return s;
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}
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} else {
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return Status::InvalidArgument(
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dbname_, "does not exist (create_if_missing is false)");
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}
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} else {
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if (options_.error_if_exists) {
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return Status::InvalidArgument(
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dbname_, "exists (error_if_exists is true)");
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}
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}
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s = versions_->Recover();
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if (s.ok()) {
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SequenceNumber max_sequence(0);
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// Recover from all newer log files than the ones named in the
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// descriptor (new log files may have been added by the previous
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// incarnation without registering them in the descriptor).
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//
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// Note that PrevLogNumber() is no longer used, but we pay
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// attention to it in case we are recovering a database
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// produced by an older version of leveldb.
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const uint64_t min_log = versions_->LogNumber();
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const uint64_t prev_log = versions_->PrevLogNumber();
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std::vector<std::string> filenames;
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|
s = env_->GetChildren(dbname_, &filenames);
|
|
if (!s.ok()) {
|
|
return s;
|
|
}
|
|
uint64_t number;
|
|
FileType type;
|
|
std::vector<uint64_t> logs;
|
|
for (size_t i = 0; i < filenames.size(); i++) {
|
|
if (ParseFileName(filenames[i], &number, &type)
|
|
&& type == kLogFile
|
|
&& ((number >= min_log) || (number == prev_log))) {
|
|
logs.push_back(number);
|
|
}
|
|
}
|
|
|
|
// Recover in the order in which the logs were generated
|
|
std::sort(logs.begin(), logs.end());
|
|
for (size_t i = 0; i < logs.size(); i++) {
|
|
s = RecoverLogFile(logs[i], edit, &max_sequence);
|
|
|
|
// The previous incarnation may not have written any MANIFEST
|
|
// records after allocating this log number. So we manually
|
|
// update the file number allocation counter in VersionSet.
|
|
versions_->MarkFileNumberUsed(logs[i]);
|
|
}
|
|
|
|
if (s.ok()) {
|
|
if (versions_->LastSequence() < max_sequence) {
|
|
versions_->SetLastSequence(max_sequence);
|
|
}
|
|
}
|
|
}
|
|
|
|
return s;
|
|
}
|
|
|
|
Status DBImpl::RecoverLogFile(uint64_t log_number,
|
|
VersionEdit* edit,
|
|
SequenceNumber* max_sequence) {
|
|
struct LogReporter : public log::Reader::Reporter {
|
|
Env* env;
|
|
Logger* info_log;
|
|
const char* fname;
|
|
Status* status; // NULL if options_.paranoid_checks==false
|
|
virtual void Corruption(size_t bytes, const Status& s) {
|
|
Log(info_log, "%s%s: dropping %d bytes; %s",
|
|
(this->status == NULL ? "(ignoring error) " : ""),
|
|
fname, static_cast<int>(bytes), s.ToString().c_str());
|
|
if (this->status != NULL && this->status->ok()) *this->status = s;
|
|
}
|
|
};
|
|
|
|
mutex_.AssertHeld();
|
|
|
|
// Open the log file
|
|
std::string fname = LogFileName(dbname_, log_number);
|
|
SequentialFile* file;
|
|
Status status = env_->NewSequentialFile(fname, &file);
|
|
if (!status.ok()) {
|
|
MaybeIgnoreError(&status);
|
|
return status;
|
|
}
|
|
|
|
// Create the log reader.
|
|
LogReporter reporter;
|
|
reporter.env = env_;
|
|
reporter.info_log = options_.info_log;
|
|
reporter.fname = fname.c_str();
|
|
reporter.status = (options_.paranoid_checks ? &status : NULL);
|
|
// We intentially make log::Reader do checksumming even if
|
|
// paranoid_checks==false so that corruptions cause entire commits
|
|
// to be skipped instead of propagating bad information (like overly
|
|
// large sequence numbers).
|
|
log::Reader reader(file, &reporter, true/*checksum*/,
|
|
0/*initial_offset*/);
|
|
Log(options_.info_log, "Recovering log #%llu",
|
|
(unsigned long long) log_number);
|
|
|
|
// Read all the records and add to a memtable
|
|
std::string scratch;
|
|
Slice record;
|
|
WriteBatch batch;
|
|
MemTable* mem = NULL;
|
|
while (reader.ReadRecord(&record, &scratch) &&
|
|
status.ok()) {
|
|
if (record.size() < 12) {
|
|
reporter.Corruption(
|
|
record.size(), Status::Corruption("log record too small"));
|
|
continue;
|
|
}
|
|
WriteBatchInternal::SetContents(&batch, record);
|
|
|
|
if (mem == NULL) {
|
|
mem = new MemTable(internal_comparator_);
|
|
mem->Ref();
|
|
}
|
|
status = WriteBatchInternal::InsertInto(&batch, mem);
|
|
MaybeIgnoreError(&status);
|
|
if (!status.ok()) {
|
|
break;
|
|
}
|
|
const SequenceNumber last_seq =
|
|
WriteBatchInternal::Sequence(&batch) +
|
|
WriteBatchInternal::Count(&batch) - 1;
|
|
if (last_seq > *max_sequence) {
|
|
*max_sequence = last_seq;
|
|
}
|
|
|
|
if (mem->ApproximateMemoryUsage() > options_.write_buffer_size) {
|
|
status = WriteLevel0Table(mem, edit, NULL);
|
|
if (!status.ok()) {
|
|
// Reflect errors immediately so that conditions like full
|
|
// file-systems cause the DB::Open() to fail.
|
|
break;
|
|
}
|
|
mem->Unref();
|
|
mem = NULL;
|
|
}
|
|
}
|
|
|
|
if (status.ok() && mem != NULL) {
|
|
status = WriteLevel0Table(mem, edit, NULL);
|
|
// Reflect errors immediately so that conditions like full
|
|
// file-systems cause the DB::Open() to fail.
|
|
}
|
|
|
|
if (mem != NULL) mem->Unref();
|
|
delete file;
|
|
return status;
|
|
}
|
|
|
|
Status DBImpl::WriteLevel0Table(MemTable* mem, VersionEdit* edit,
|
|
Version* base) {
|
|
mutex_.AssertHeld();
|
|
const uint64_t start_micros = env_->NowMicros();
|
|
FileMetaData meta;
|
|
meta.number = versions_->NewFileNumber();
|
|
pending_outputs_.insert(meta.number);
|
|
Iterator* iter = mem->NewIterator();
|
|
Log(options_.info_log, "Level-0 table #%llu: started",
|
|
(unsigned long long) meta.number);
|
|
|
|
Status s;
|
|
{
|
|
mutex_.Unlock();
|
|
s = BuildTable(dbname_, env_, options_, table_cache_, iter, &meta);
|
|
mutex_.Lock();
|
|
}
|
|
|
|
Log(options_.info_log, "Level-0 table #%llu: %lld bytes %s",
|
|
(unsigned long long) meta.number,
|
|
(unsigned long long) meta.file_size,
|
|
s.ToString().c_str());
|
|
delete iter;
|
|
pending_outputs_.erase(meta.number);
|
|
|
|
|
|
// Note that if file_size is zero, the file has been deleted and
|
|
// should not be added to the manifest.
|
|
int level = 0;
|
|
if (s.ok() && meta.file_size > 0) {
|
|
const Slice min_user_key = meta.smallest.user_key();
|
|
const Slice max_user_key = meta.largest.user_key();
|
|
if (base != NULL) {
|
|
level = base->PickLevelForMemTableOutput(min_user_key, max_user_key);
|
|
}
|
|
edit->AddFile(level, meta.number, meta.file_size,
|
|
meta.smallest, meta.largest);
|
|
}
|
|
|
|
CompactionStats stats;
|
|
stats.micros = env_->NowMicros() - start_micros;
|
|
stats.bytes_written = meta.file_size;
|
|
stats.files_out_levelnp1 = 1;
|
|
stats_[level].Add(stats);
|
|
return s;
|
|
}
|
|
|
|
Status DBImpl::CompactMemTable() {
|
|
mutex_.AssertHeld();
|
|
assert(imm_ != NULL);
|
|
|
|
// Save the contents of the memtable as a new Table
|
|
VersionEdit edit(NumberLevels());
|
|
Version* base = versions_->current();
|
|
base->Ref();
|
|
Status s = WriteLevel0Table(imm_, &edit, base);
|
|
base->Unref();
|
|
|
|
if (s.ok() && shutting_down_.Acquire_Load()) {
|
|
s = Status::IOError("Deleting DB during memtable compaction");
|
|
}
|
|
|
|
// Replace immutable memtable with the generated Table
|
|
if (s.ok()) {
|
|
edit.SetPrevLogNumber(0);
|
|
edit.SetLogNumber(logfile_number_); // Earlier logs no longer needed
|
|
s = versions_->LogAndApply(&edit, &mutex_);
|
|
}
|
|
|
|
if (s.ok()) {
|
|
// Commit to the new state
|
|
imm_->Unref();
|
|
imm_ = NULL;
|
|
has_imm_.Release_Store(NULL);
|
|
MaybeScheduleLogDBDeployStats();
|
|
// we could have deleted obsolete files here, but it is not
|
|
// absolutely necessary because it could be also done as part
|
|
// of other background compaction
|
|
}
|
|
|
|
return s;
|
|
}
|
|
|
|
void DBImpl::CompactRange(const Slice* begin, const Slice* end) {
|
|
int max_level_with_files = 1;
|
|
{
|
|
MutexLock l(&mutex_);
|
|
Version* base = versions_->current();
|
|
for (int level = 1; level < NumberLevels(); level++) {
|
|
if (base->OverlapInLevel(level, begin, end)) {
|
|
max_level_with_files = level;
|
|
}
|
|
}
|
|
}
|
|
TEST_CompactMemTable(); // TODO(sanjay): Skip if memtable does not overlap
|
|
for (int level = 0; level < max_level_with_files; level++) {
|
|
TEST_CompactRange(level, begin, end);
|
|
}
|
|
}
|
|
|
|
int DBImpl::NumberLevels() {
|
|
return options_.num_levels;
|
|
}
|
|
|
|
int DBImpl::MaxMemCompactionLevel() {
|
|
return options_.max_mem_compaction_level;
|
|
}
|
|
|
|
int DBImpl::Level0StopWriteTrigger() {
|
|
return options_.level0_stop_writes_trigger;
|
|
}
|
|
|
|
Status DBImpl::Flush(const FlushOptions& options) {
|
|
Status status = FlushMemTable(options);
|
|
return status;
|
|
}
|
|
|
|
void DBImpl::TEST_CompactRange(int level, const Slice* begin,const Slice* end) {
|
|
assert(level >= 0);
|
|
|
|
InternalKey begin_storage, end_storage;
|
|
|
|
ManualCompaction manual;
|
|
manual.level = level;
|
|
manual.done = false;
|
|
if (begin == NULL) {
|
|
manual.begin = NULL;
|
|
} else {
|
|
begin_storage = InternalKey(*begin, kMaxSequenceNumber, kValueTypeForSeek);
|
|
manual.begin = &begin_storage;
|
|
}
|
|
if (end == NULL) {
|
|
manual.end = NULL;
|
|
} else {
|
|
end_storage = InternalKey(*end, 0, static_cast<ValueType>(0));
|
|
manual.end = &end_storage;
|
|
}
|
|
|
|
MutexLock l(&mutex_);
|
|
while (!manual.done) {
|
|
while (manual_compaction_ != NULL) {
|
|
bg_cv_.Wait();
|
|
}
|
|
manual_compaction_ = &manual;
|
|
MaybeScheduleCompaction();
|
|
while (manual_compaction_ == &manual) {
|
|
bg_cv_.Wait();
|
|
}
|
|
}
|
|
}
|
|
|
|
Status DBImpl::FlushMemTable(const FlushOptions& options) {
|
|
// NULL batch means just wait for earlier writes to be done
|
|
Status s = Write(WriteOptions(), NULL);
|
|
if (s.ok() && options.wait) {
|
|
// Wait until the compaction completes
|
|
s = WaitForCompactMemTable();
|
|
}
|
|
return s;
|
|
}
|
|
|
|
Status DBImpl::WaitForCompactMemTable() {
|
|
Status s;
|
|
// Wait until the compaction completes
|
|
MutexLock l(&mutex_);
|
|
while (imm_ != NULL && bg_error_.ok()) {
|
|
bg_cv_.Wait();
|
|
}
|
|
if (imm_ != NULL) {
|
|
s = bg_error_;
|
|
}
|
|
return s;
|
|
}
|
|
|
|
Status DBImpl::TEST_CompactMemTable() {
|
|
return FlushMemTable(FlushOptions());
|
|
}
|
|
|
|
Status DBImpl::TEST_WaitForCompactMemTable() {
|
|
return WaitForCompactMemTable();
|
|
}
|
|
|
|
Status DBImpl::TEST_WaitForCompact() {
|
|
// Wait until the compaction completes
|
|
MutexLock l(&mutex_);
|
|
while (bg_compaction_scheduled_ && bg_error_.ok()) {
|
|
bg_cv_.Wait();
|
|
}
|
|
return bg_error_;
|
|
}
|
|
|
|
void DBImpl::MaybeScheduleCompaction() {
|
|
mutex_.AssertHeld();
|
|
if (bg_compaction_scheduled_) {
|
|
// Already scheduled
|
|
} else if (shutting_down_.Acquire_Load()) {
|
|
// DB is being deleted; no more background compactions
|
|
} else if (imm_ == NULL &&
|
|
manual_compaction_ == NULL &&
|
|
!versions_->NeedsCompaction()) {
|
|
// No work to be done
|
|
} else {
|
|
bg_compaction_scheduled_ = true;
|
|
env_->Schedule(&DBImpl::BGWork, this);
|
|
}
|
|
}
|
|
|
|
void DBImpl::BGWork(void* db) {
|
|
reinterpret_cast<DBImpl*>(db)->BackgroundCall();
|
|
}
|
|
|
|
void DBImpl::BackgroundCall() {
|
|
DeletionState deletion_state;
|
|
MutexLock l(&mutex_);
|
|
assert(bg_compaction_scheduled_);
|
|
if (!shutting_down_.Acquire_Load()) {
|
|
Status s = BackgroundCompaction(deletion_state);
|
|
if (!s.ok()) {
|
|
// Wait a little bit before retrying background compaction in
|
|
// case this is an environmental problem and we do not want to
|
|
// chew up resources for failed compactions for the duration of
|
|
// the problem.
|
|
bg_cv_.SignalAll(); // In case a waiter can proceed despite the error
|
|
Log(options_.info_log, "Waiting after background compaction error: %s",
|
|
s.ToString().c_str());
|
|
mutex_.Unlock();
|
|
env_->SleepForMicroseconds(1000000);
|
|
mutex_.Lock();
|
|
}
|
|
}
|
|
|
|
// delete unnecessary files if any, this is done outside the mutex
|
|
if (!deletion_state.live.empty()) {
|
|
mutex_.Unlock();
|
|
PurgeObsoleteFiles(deletion_state);
|
|
mutex_.Lock();
|
|
EvictObsoleteFiles(deletion_state);
|
|
}
|
|
|
|
bg_compaction_scheduled_ = false;
|
|
|
|
MaybeScheduleLogDBDeployStats();
|
|
|
|
// Previous compaction may have produced too many files in a level,
|
|
// so reschedule another compaction if needed.
|
|
MaybeScheduleCompaction();
|
|
bg_cv_.SignalAll();
|
|
}
|
|
|
|
Status DBImpl::BackgroundCompaction(DeletionState& deletion_state) {
|
|
mutex_.AssertHeld();
|
|
|
|
if (imm_ != NULL) {
|
|
return CompactMemTable();
|
|
}
|
|
|
|
Compaction* c;
|
|
bool is_manual = (manual_compaction_ != NULL);
|
|
InternalKey manual_end;
|
|
if (is_manual) {
|
|
ManualCompaction* m = manual_compaction_;
|
|
c = versions_->CompactRange(m->level, m->begin, m->end);
|
|
m->done = (c == NULL);
|
|
if (c != NULL) {
|
|
manual_end = c->input(0, c->num_input_files(0) - 1)->largest;
|
|
}
|
|
Log(options_.info_log,
|
|
"Manual compaction at level-%d from %s .. %s; will stop at %s\n",
|
|
m->level,
|
|
(m->begin ? m->begin->DebugString().c_str() : "(begin)"),
|
|
(m->end ? m->end->DebugString().c_str() : "(end)"),
|
|
(m->done ? "(end)" : manual_end.DebugString().c_str()));
|
|
} else {
|
|
c = versions_->PickCompaction();
|
|
}
|
|
|
|
Status status;
|
|
if (c == NULL) {
|
|
// Nothing to do
|
|
} else if (!is_manual && c->IsTrivialMove()) {
|
|
// Move file to next level
|
|
assert(c->num_input_files(0) == 1);
|
|
FileMetaData* f = c->input(0, 0);
|
|
c->edit()->DeleteFile(c->level(), f->number);
|
|
c->edit()->AddFile(c->level() + 1, f->number, f->file_size,
|
|
f->smallest, f->largest);
|
|
status = versions_->LogAndApply(c->edit(), &mutex_);
|
|
VersionSet::LevelSummaryStorage tmp;
|
|
Log(options_.info_log, "Moved #%lld to level-%d %lld bytes %s: %s\n",
|
|
static_cast<unsigned long long>(f->number),
|
|
c->level() + 1,
|
|
static_cast<unsigned long long>(f->file_size),
|
|
status.ToString().c_str(),
|
|
versions_->LevelSummary(&tmp));
|
|
} else {
|
|
CompactionState* compact = new CompactionState(c);
|
|
status = DoCompactionWork(compact);
|
|
CleanupCompaction(compact);
|
|
c->ReleaseInputs();
|
|
FindObsoleteFiles(deletion_state);
|
|
}
|
|
delete c;
|
|
|
|
if (status.ok()) {
|
|
// Done
|
|
} else if (shutting_down_.Acquire_Load()) {
|
|
// Ignore compaction errors found during shutting down
|
|
} else {
|
|
Log(options_.info_log,
|
|
"Compaction error: %s", status.ToString().c_str());
|
|
if (options_.paranoid_checks && bg_error_.ok()) {
|
|
bg_error_ = status;
|
|
}
|
|
}
|
|
|
|
if (is_manual) {
|
|
ManualCompaction* m = manual_compaction_;
|
|
if (!status.ok()) {
|
|
m->done = true;
|
|
}
|
|
if (!m->done) {
|
|
// We only compacted part of the requested range. Update *m
|
|
// to the range that is left to be compacted.
|
|
m->tmp_storage = manual_end;
|
|
m->begin = &m->tmp_storage;
|
|
}
|
|
manual_compaction_ = NULL;
|
|
}
|
|
return status;
|
|
}
|
|
|
|
void DBImpl::CleanupCompaction(CompactionState* compact) {
|
|
mutex_.AssertHeld();
|
|
if (compact->builder != NULL) {
|
|
// May happen if we get a shutdown call in the middle of compaction
|
|
compact->builder->Abandon();
|
|
delete compact->builder;
|
|
} else {
|
|
assert(compact->outfile == NULL);
|
|
}
|
|
delete compact->outfile;
|
|
for (size_t i = 0; i < compact->outputs.size(); i++) {
|
|
const CompactionState::Output& out = compact->outputs[i];
|
|
pending_outputs_.erase(out.number);
|
|
}
|
|
delete compact;
|
|
}
|
|
|
|
Status DBImpl::OpenCompactionOutputFile(CompactionState* compact) {
|
|
assert(compact != NULL);
|
|
assert(compact->builder == NULL);
|
|
uint64_t file_number;
|
|
{
|
|
mutex_.Lock();
|
|
file_number = versions_->NewFileNumber();
|
|
pending_outputs_.insert(file_number);
|
|
CompactionState::Output out;
|
|
out.number = file_number;
|
|
out.smallest.Clear();
|
|
out.largest.Clear();
|
|
compact->outputs.push_back(out);
|
|
mutex_.Unlock();
|
|
}
|
|
|
|
// Make the output file
|
|
std::string fname = TableFileName(dbname_, file_number);
|
|
Status s = env_->NewWritableFile(fname, &compact->outfile);
|
|
if (s.ok()) {
|
|
compact->builder = new TableBuilder(options_, compact->outfile,
|
|
compact->compaction->level() + 1);
|
|
}
|
|
return s;
|
|
}
|
|
|
|
Status DBImpl::FinishCompactionOutputFile(CompactionState* compact,
|
|
Iterator* input) {
|
|
assert(compact != NULL);
|
|
assert(compact->outfile != NULL);
|
|
assert(compact->builder != NULL);
|
|
|
|
const uint64_t output_number = compact->current_output()->number;
|
|
assert(output_number != 0);
|
|
|
|
// Check for iterator errors
|
|
Status s = input->status();
|
|
const uint64_t current_entries = compact->builder->NumEntries();
|
|
if (s.ok()) {
|
|
s = compact->builder->Finish();
|
|
} else {
|
|
compact->builder->Abandon();
|
|
}
|
|
const uint64_t current_bytes = compact->builder->FileSize();
|
|
compact->current_output()->file_size = current_bytes;
|
|
compact->total_bytes += current_bytes;
|
|
delete compact->builder;
|
|
compact->builder = NULL;
|
|
|
|
// Finish and check for file errors
|
|
if (s.ok() && !options_.disableDataSync) {
|
|
if (options_.use_fsync) {
|
|
s = compact->outfile->Fsync();
|
|
} else {
|
|
s = compact->outfile->Sync();
|
|
}
|
|
}
|
|
if (s.ok()) {
|
|
s = compact->outfile->Close();
|
|
}
|
|
delete compact->outfile;
|
|
compact->outfile = NULL;
|
|
|
|
if (s.ok() && current_entries > 0) {
|
|
// Verify that the table is usable
|
|
Iterator* iter = table_cache_->NewIterator(ReadOptions(),
|
|
output_number,
|
|
current_bytes);
|
|
s = iter->status();
|
|
delete iter;
|
|
if (s.ok()) {
|
|
Log(options_.info_log,
|
|
"Generated table #%llu: %lld keys, %lld bytes",
|
|
(unsigned long long) output_number,
|
|
(unsigned long long) current_entries,
|
|
(unsigned long long) current_bytes);
|
|
}
|
|
}
|
|
return s;
|
|
}
|
|
|
|
|
|
Status DBImpl::InstallCompactionResults(CompactionState* compact) {
|
|
mutex_.AssertHeld();
|
|
Log(options_.info_log, "Compacted %d@%d + %d@%d files => %lld bytes",
|
|
compact->compaction->num_input_files(0),
|
|
compact->compaction->level(),
|
|
compact->compaction->num_input_files(1),
|
|
compact->compaction->level() + 1,
|
|
static_cast<long long>(compact->total_bytes));
|
|
|
|
// Add compaction outputs
|
|
compact->compaction->AddInputDeletions(compact->compaction->edit());
|
|
const int level = compact->compaction->level();
|
|
for (size_t i = 0; i < compact->outputs.size(); i++) {
|
|
const CompactionState::Output& out = compact->outputs[i];
|
|
compact->compaction->edit()->AddFile(
|
|
level + 1,
|
|
out.number, out.file_size, out.smallest, out.largest);
|
|
}
|
|
return versions_->LogAndApply(compact->compaction->edit(), &mutex_);
|
|
}
|
|
|
|
Status DBImpl::DoCompactionWork(CompactionState* compact) {
|
|
const uint64_t start_micros = env_->NowMicros();
|
|
int64_t imm_micros = 0; // Micros spent doing imm_ compactions
|
|
|
|
Log(options_.info_log, "Compacting %d@%d + %d@%d files",
|
|
compact->compaction->num_input_files(0),
|
|
compact->compaction->level(),
|
|
compact->compaction->num_input_files(1),
|
|
compact->compaction->level() + 1);
|
|
char scratch[256];
|
|
compact->compaction->Summary(scratch, sizeof(scratch));
|
|
Log(options_.info_log, "Compaction start summary: %s\n", scratch);
|
|
|
|
assert(versions_->NumLevelFiles(compact->compaction->level()) > 0);
|
|
assert(compact->builder == NULL);
|
|
assert(compact->outfile == NULL);
|
|
if (snapshots_.empty()) {
|
|
compact->smallest_snapshot = versions_->LastSequence();
|
|
} else {
|
|
compact->smallest_snapshot = snapshots_.oldest()->number_;
|
|
}
|
|
|
|
// Release mutex while we're actually doing the compaction work
|
|
mutex_.Unlock();
|
|
|
|
Iterator* input = versions_->MakeInputIterator(compact->compaction);
|
|
input->SeekToFirst();
|
|
Status status;
|
|
ParsedInternalKey ikey;
|
|
std::string current_user_key;
|
|
bool has_current_user_key = false;
|
|
SequenceNumber last_sequence_for_key = kMaxSequenceNumber;
|
|
for (; input->Valid() && !shutting_down_.Acquire_Load(); ) {
|
|
// Prioritize immutable compaction work
|
|
if (has_imm_.NoBarrier_Load() != NULL) {
|
|
const uint64_t imm_start = env_->NowMicros();
|
|
mutex_.Lock();
|
|
if (imm_ != NULL) {
|
|
CompactMemTable();
|
|
bg_cv_.SignalAll(); // Wakeup MakeRoomForWrite() if necessary
|
|
}
|
|
mutex_.Unlock();
|
|
imm_micros += (env_->NowMicros() - imm_start);
|
|
}
|
|
|
|
Slice key = input->key();
|
|
if (compact->compaction->ShouldStopBefore(key) &&
|
|
compact->builder != NULL) {
|
|
status = FinishCompactionOutputFile(compact, input);
|
|
if (!status.ok()) {
|
|
break;
|
|
}
|
|
}
|
|
|
|
// Handle key/value, add to state, etc.
|
|
bool drop = false;
|
|
if (!ParseInternalKey(key, &ikey)) {
|
|
// Do not hide error keys
|
|
current_user_key.clear();
|
|
has_current_user_key = false;
|
|
last_sequence_for_key = kMaxSequenceNumber;
|
|
} else {
|
|
if (!has_current_user_key ||
|
|
user_comparator()->Compare(ikey.user_key,
|
|
Slice(current_user_key)) != 0) {
|
|
// First occurrence of this user key
|
|
current_user_key.assign(ikey.user_key.data(), ikey.user_key.size());
|
|
has_current_user_key = true;
|
|
last_sequence_for_key = kMaxSequenceNumber;
|
|
}
|
|
|
|
if (last_sequence_for_key <= compact->smallest_snapshot) {
|
|
// Hidden by an newer entry for same user key
|
|
drop = true; // (A)
|
|
} else if (ikey.type == kTypeDeletion &&
|
|
ikey.sequence <= compact->smallest_snapshot &&
|
|
compact->compaction->IsBaseLevelForKey(ikey.user_key)) {
|
|
// For this user key:
|
|
// (1) there is no data in higher levels
|
|
// (2) data in lower levels will have larger sequence numbers
|
|
// (3) data in layers that are being compacted here and have
|
|
// smaller sequence numbers will be dropped in the next
|
|
// few iterations of this loop (by rule (A) above).
|
|
// Therefore this deletion marker is obsolete and can be dropped.
|
|
drop = true;
|
|
}
|
|
|
|
last_sequence_for_key = ikey.sequence;
|
|
}
|
|
#if 0
|
|
Log(options_.info_log,
|
|
" Compact: %s, seq %d, type: %d %d, drop: %d, is_base: %d, "
|
|
"%d smallest_snapshot: %d",
|
|
ikey.user_key.ToString().c_str(),
|
|
(int)ikey.sequence, ikey.type, kTypeValue, drop,
|
|
compact->compaction->IsBaseLevelForKey(ikey.user_key),
|
|
(int)last_sequence_for_key, (int)compact->smallest_snapshot);
|
|
#endif
|
|
|
|
if (!drop) {
|
|
// Open output file if necessary
|
|
if (compact->builder == NULL) {
|
|
status = OpenCompactionOutputFile(compact);
|
|
if (!status.ok()) {
|
|
break;
|
|
}
|
|
}
|
|
if (compact->builder->NumEntries() == 0) {
|
|
compact->current_output()->smallest.DecodeFrom(key);
|
|
}
|
|
compact->current_output()->largest.DecodeFrom(key);
|
|
compact->builder->Add(key, input->value());
|
|
|
|
// Close output file if it is big enough
|
|
if (compact->builder->FileSize() >=
|
|
compact->compaction->MaxOutputFileSize()) {
|
|
status = FinishCompactionOutputFile(compact, input);
|
|
if (!status.ok()) {
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
|
|
input->Next();
|
|
}
|
|
|
|
if (status.ok() && shutting_down_.Acquire_Load()) {
|
|
status = Status::IOError("Deleting DB during compaction");
|
|
}
|
|
if (status.ok() && compact->builder != NULL) {
|
|
status = FinishCompactionOutputFile(compact, input);
|
|
}
|
|
if (status.ok()) {
|
|
status = input->status();
|
|
}
|
|
delete input;
|
|
input = NULL;
|
|
|
|
CompactionStats stats;
|
|
stats.micros = env_->NowMicros() - start_micros - imm_micros;
|
|
|
|
stats.files_in_leveln = compact->compaction->num_input_files(0);
|
|
stats.files_in_levelnp1 = compact->compaction->num_input_files(1);
|
|
stats.files_out_levelnp1 = compact->outputs.size();
|
|
|
|
for (int i = 0; i < compact->compaction->num_input_files(0); i++)
|
|
stats.bytes_readn += compact->compaction->input(0, i)->file_size;
|
|
|
|
for (int i = 0; i < compact->compaction->num_input_files(1); i++)
|
|
stats.bytes_readnp1 += compact->compaction->input(1, i)->file_size;
|
|
|
|
for (size_t i = 0; i < compact->outputs.size(); i++) {
|
|
stats.bytes_written += compact->outputs[i].file_size;
|
|
}
|
|
|
|
mutex_.Lock();
|
|
stats_[compact->compaction->level() + 1].Add(stats);
|
|
|
|
if (status.ok()) {
|
|
status = InstallCompactionResults(compact);
|
|
}
|
|
VersionSet::LevelSummaryStorage tmp;
|
|
Log(options_.info_log,
|
|
"compacted to: %s, %.1f MB/sec, level %d, files in(%d, %d) out(%d) "
|
|
"MB in(%.1f, %.1f) out(%.1f), amplify(%.1f)\n",
|
|
versions_->LevelSummary(&tmp),
|
|
(stats.bytes_readn + stats.bytes_readnp1 + stats.bytes_written) /
|
|
(double) stats.micros,
|
|
compact->compaction->level() + 1,
|
|
stats.files_in_leveln, stats.files_in_levelnp1, stats.files_out_levelnp1,
|
|
stats.bytes_readn / 1048576.0,
|
|
stats.bytes_readnp1 / 1048576.0,
|
|
stats.bytes_written / 1048576.0,
|
|
(stats.bytes_written + stats.bytes_readnp1) /
|
|
(double) stats.bytes_readn);
|
|
|
|
return status;
|
|
}
|
|
|
|
namespace {
|
|
struct IterState {
|
|
port::Mutex* mu;
|
|
Version* version;
|
|
MemTable* mem;
|
|
MemTable* imm;
|
|
};
|
|
|
|
static void CleanupIteratorState(void* arg1, void* arg2) {
|
|
IterState* state = reinterpret_cast<IterState*>(arg1);
|
|
state->mu->Lock();
|
|
state->mem->Unref();
|
|
if (state->imm != NULL) state->imm->Unref();
|
|
state->version->Unref();
|
|
state->mu->Unlock();
|
|
delete state;
|
|
}
|
|
} // namespace
|
|
|
|
Iterator* DBImpl::NewInternalIterator(const ReadOptions& options,
|
|
SequenceNumber* latest_snapshot) {
|
|
IterState* cleanup = new IterState;
|
|
mutex_.Lock();
|
|
*latest_snapshot = versions_->LastSequence();
|
|
|
|
// Collect together all needed child iterators
|
|
std::vector<Iterator*> list;
|
|
list.push_back(mem_->NewIterator());
|
|
mem_->Ref();
|
|
if (imm_ != NULL) {
|
|
list.push_back(imm_->NewIterator());
|
|
imm_->Ref();
|
|
}
|
|
versions_->current()->AddIterators(options, &list);
|
|
Iterator* internal_iter =
|
|
NewMergingIterator(&internal_comparator_, &list[0], list.size());
|
|
versions_->current()->Ref();
|
|
|
|
cleanup->mu = &mutex_;
|
|
cleanup->mem = mem_;
|
|
cleanup->imm = imm_;
|
|
cleanup->version = versions_->current();
|
|
internal_iter->RegisterCleanup(CleanupIteratorState, cleanup, NULL);
|
|
|
|
mutex_.Unlock();
|
|
return internal_iter;
|
|
}
|
|
|
|
Iterator* DBImpl::TEST_NewInternalIterator() {
|
|
SequenceNumber ignored;
|
|
return NewInternalIterator(ReadOptions(), &ignored);
|
|
}
|
|
|
|
int64_t DBImpl::TEST_MaxNextLevelOverlappingBytes() {
|
|
MutexLock l(&mutex_);
|
|
return versions_->MaxNextLevelOverlappingBytes();
|
|
}
|
|
|
|
Status DBImpl::Get(const ReadOptions& options,
|
|
const Slice& key,
|
|
std::string* value) {
|
|
Status s;
|
|
MutexLock l(&mutex_);
|
|
SequenceNumber snapshot;
|
|
if (options.snapshot != NULL) {
|
|
snapshot = reinterpret_cast<const SnapshotImpl*>(options.snapshot)->number_;
|
|
} else {
|
|
snapshot = versions_->LastSequence();
|
|
}
|
|
|
|
MemTable* mem = mem_;
|
|
MemTable* imm = imm_;
|
|
Version* current = versions_->current();
|
|
mem->Ref();
|
|
if (imm != NULL) imm->Ref();
|
|
current->Ref();
|
|
|
|
bool have_stat_update = false;
|
|
Version::GetStats stats;
|
|
|
|
// Unlock while reading from files and memtables
|
|
{
|
|
mutex_.Unlock();
|
|
// First look in the memtable, then in the immutable memtable (if any).
|
|
LookupKey lkey(key, snapshot);
|
|
if (mem->Get(lkey, value, &s)) {
|
|
// Done
|
|
} else if (imm != NULL && imm->Get(lkey, value, &s)) {
|
|
// Done
|
|
} else {
|
|
s = current->Get(options, lkey, value, &stats);
|
|
have_stat_update = true;
|
|
}
|
|
mutex_.Lock();
|
|
}
|
|
|
|
if (!options_.disable_seek_compaction &&
|
|
have_stat_update && current->UpdateStats(stats)) {
|
|
MaybeScheduleCompaction();
|
|
}
|
|
mem->Unref();
|
|
if (imm != NULL) imm->Unref();
|
|
current->Unref();
|
|
return s;
|
|
}
|
|
|
|
Iterator* DBImpl::NewIterator(const ReadOptions& options) {
|
|
SequenceNumber latest_snapshot;
|
|
Iterator* internal_iter = NewInternalIterator(options, &latest_snapshot);
|
|
return NewDBIterator(
|
|
&dbname_, env_, user_comparator(), internal_iter,
|
|
(options.snapshot != NULL
|
|
? reinterpret_cast<const SnapshotImpl*>(options.snapshot)->number_
|
|
: latest_snapshot));
|
|
}
|
|
|
|
const Snapshot* DBImpl::GetSnapshot() {
|
|
MutexLock l(&mutex_);
|
|
return snapshots_.New(versions_->LastSequence());
|
|
}
|
|
|
|
void DBImpl::ReleaseSnapshot(const Snapshot* s) {
|
|
MutexLock l(&mutex_);
|
|
snapshots_.Delete(reinterpret_cast<const SnapshotImpl*>(s));
|
|
}
|
|
|
|
// Convenience methods
|
|
Status DBImpl::Put(const WriteOptions& o, const Slice& key, const Slice& val) {
|
|
return DB::Put(o, key, val);
|
|
}
|
|
|
|
Status DBImpl::Delete(const WriteOptions& options, const Slice& key) {
|
|
return DB::Delete(options, key);
|
|
}
|
|
|
|
Status DBImpl::Write(const WriteOptions& options, WriteBatch* my_batch) {
|
|
Writer w(&mutex_);
|
|
w.batch = my_batch;
|
|
w.sync = options.sync;
|
|
w.disableWAL = options.disableWAL;
|
|
w.done = false;
|
|
|
|
MutexLock l(&mutex_);
|
|
writers_.push_back(&w);
|
|
while (!w.done && &w != writers_.front()) {
|
|
w.cv.Wait();
|
|
}
|
|
if (w.done) {
|
|
return w.status;
|
|
}
|
|
|
|
// May temporarily unlock and wait.
|
|
Status status = MakeRoomForWrite(my_batch == NULL);
|
|
uint64_t last_sequence = versions_->LastSequence();
|
|
Writer* last_writer = &w;
|
|
if (status.ok() && my_batch != NULL) { // NULL batch is for compactions
|
|
WriteBatch* updates = BuildBatchGroup(&last_writer);
|
|
WriteBatchInternal::SetSequence(updates, last_sequence + 1);
|
|
last_sequence += WriteBatchInternal::Count(updates);
|
|
|
|
// Add to log and apply to memtable. We can release the lock
|
|
// during this phase since &w is currently responsible for logging
|
|
// and protects against concurrent loggers and concurrent writes
|
|
// into mem_.
|
|
{
|
|
mutex_.Unlock();
|
|
if (!options.disableWAL) {
|
|
status = log_->AddRecord(WriteBatchInternal::Contents(updates));
|
|
if (status.ok() && options.sync) {
|
|
if (options_.use_fsync) {
|
|
status = logfile_->Fsync();
|
|
} else {
|
|
status = logfile_->Sync();
|
|
}
|
|
}
|
|
}
|
|
if (status.ok()) {
|
|
status = WriteBatchInternal::InsertInto(updates, mem_);
|
|
}
|
|
mutex_.Lock();
|
|
}
|
|
if (updates == tmp_batch_) tmp_batch_->Clear();
|
|
|
|
versions_->SetLastSequence(last_sequence);
|
|
}
|
|
|
|
while (true) {
|
|
Writer* ready = writers_.front();
|
|
writers_.pop_front();
|
|
if (ready != &w) {
|
|
ready->status = status;
|
|
ready->done = true;
|
|
ready->cv.Signal();
|
|
}
|
|
if (ready == last_writer) break;
|
|
}
|
|
|
|
// Notify new head of write queue
|
|
if (!writers_.empty()) {
|
|
writers_.front()->cv.Signal();
|
|
}
|
|
|
|
return status;
|
|
}
|
|
|
|
// REQUIRES: Writer list must be non-empty
|
|
// REQUIRES: First writer must have a non-NULL batch
|
|
WriteBatch* DBImpl::BuildBatchGroup(Writer** last_writer) {
|
|
assert(!writers_.empty());
|
|
Writer* first = writers_.front();
|
|
WriteBatch* result = first->batch;
|
|
assert(result != NULL);
|
|
|
|
size_t size = WriteBatchInternal::ByteSize(first->batch);
|
|
|
|
// Allow the group to grow up to a maximum size, but if the
|
|
// original write is small, limit the growth so we do not slow
|
|
// down the small write too much.
|
|
size_t max_size = 1 << 20;
|
|
if (size <= (128<<10)) {
|
|
max_size = size + (128<<10);
|
|
}
|
|
|
|
*last_writer = first;
|
|
std::deque<Writer*>::iterator iter = writers_.begin();
|
|
++iter; // Advance past "first"
|
|
for (; iter != writers_.end(); ++iter) {
|
|
Writer* w = *iter;
|
|
if (w->sync && !first->sync) {
|
|
// Do not include a sync write into a batch handled by a non-sync write.
|
|
break;
|
|
}
|
|
|
|
if (!w->disableWAL && first->disableWAL) {
|
|
// Do not include a write that needs WAL into a batch that has
|
|
// WAL disabled.
|
|
break;
|
|
}
|
|
|
|
if (w->batch != NULL) {
|
|
size += WriteBatchInternal::ByteSize(w->batch);
|
|
if (size > max_size) {
|
|
// Do not make batch too big
|
|
break;
|
|
}
|
|
|
|
// Append to *reuslt
|
|
if (result == first->batch) {
|
|
// Switch to temporary batch instead of disturbing caller's batch
|
|
result = tmp_batch_;
|
|
assert(WriteBatchInternal::Count(result) == 0);
|
|
WriteBatchInternal::Append(result, first->batch);
|
|
}
|
|
WriteBatchInternal::Append(result, w->batch);
|
|
}
|
|
*last_writer = w;
|
|
}
|
|
return result;
|
|
}
|
|
|
|
// REQUIRES: mutex_ is held
|
|
// REQUIRES: this thread is currently at the front of the writer queue
|
|
Status DBImpl::MakeRoomForWrite(bool force) {
|
|
mutex_.AssertHeld();
|
|
assert(!writers_.empty());
|
|
bool allow_delay = !force;
|
|
Status s;
|
|
double score;
|
|
|
|
while (true) {
|
|
if (!bg_error_.ok()) {
|
|
// Yield previous error
|
|
s = bg_error_;
|
|
break;
|
|
} else if (
|
|
allow_delay &&
|
|
versions_->NumLevelFiles(0) >=
|
|
options_.level0_slowdown_writes_trigger) {
|
|
// We are getting close to hitting a hard limit on the number of
|
|
// L0 files. Rather than delaying a single write by several
|
|
// seconds when we hit the hard limit, start delaying each
|
|
// individual write by 1ms to reduce latency variance. Also,
|
|
// this delay hands over some CPU to the compaction thread in
|
|
// case it is sharing the same core as the writer.
|
|
mutex_.Unlock();
|
|
env_->SleepForMicroseconds(1000);
|
|
stall_level0_slowdown_ += 1000;
|
|
allow_delay = false; // Do not delay a single write more than once
|
|
Log(options_.info_log, "delaying write...\n");
|
|
mutex_.Lock();
|
|
} else if (!force &&
|
|
(mem_->ApproximateMemoryUsage() <= options_.write_buffer_size)) {
|
|
// There is room in current memtable
|
|
break;
|
|
} else if (imm_ != NULL) {
|
|
// We have filled up the current memtable, but the previous
|
|
// one is still being compacted, so we wait.
|
|
Log(options_.info_log, "wait for memtable compaction...\n");
|
|
uint64_t t1 = env_->NowMicros();
|
|
bg_cv_.Wait();
|
|
stall_memtable_compaction_ += env_->NowMicros() - t1;
|
|
} else if (versions_->NumLevelFiles(0) >=
|
|
options_.level0_stop_writes_trigger) {
|
|
// There are too many level-0 files.
|
|
Log(options_.info_log, "waiting...\n");
|
|
uint64_t t1 = env_->NowMicros();
|
|
bg_cv_.Wait();
|
|
stall_level0_num_files_ += env_->NowMicros() - t1;
|
|
} else if (
|
|
allow_delay &&
|
|
options_.rate_limit > 1.0 &&
|
|
(score = versions_->MaxCompactionScore()) > options_.rate_limit) {
|
|
// Delay a write when the compaction score for any level is too large.
|
|
mutex_.Unlock();
|
|
env_->SleepForMicroseconds(1000);
|
|
stall_leveln_slowdown_ += 1000;
|
|
allow_delay = false; // Do not delay a single write more than once
|
|
Log(options_.info_log,
|
|
"delaying write for rate limits with max score %.2f\n", score);
|
|
mutex_.Lock();
|
|
} else {
|
|
// Attempt to switch to a new memtable and trigger compaction of old
|
|
assert(versions_->PrevLogNumber() == 0);
|
|
uint64_t new_log_number = versions_->NewFileNumber();
|
|
WritableFile* lfile = NULL;
|
|
s = env_->NewWritableFile(LogFileName(dbname_, new_log_number), &lfile);
|
|
if (!s.ok()) {
|
|
// Avoid chewing through file number space in a tight loop.
|
|
versions_->ReuseFileNumber(new_log_number);
|
|
break;
|
|
}
|
|
delete log_;
|
|
delete logfile_;
|
|
logfile_ = lfile;
|
|
logfile_number_ = new_log_number;
|
|
log_ = new log::Writer(lfile);
|
|
imm_ = mem_;
|
|
has_imm_.Release_Store(imm_);
|
|
mem_ = new MemTable(internal_comparator_);
|
|
mem_->Ref();
|
|
force = false; // Do not force another compaction if have room
|
|
MaybeScheduleCompaction();
|
|
}
|
|
}
|
|
return s;
|
|
}
|
|
|
|
bool DBImpl::GetProperty(const Slice& property, std::string* value) {
|
|
value->clear();
|
|
|
|
MutexLock l(&mutex_);
|
|
Slice in = property;
|
|
Slice prefix("leveldb.");
|
|
if (!in.starts_with(prefix)) return false;
|
|
in.remove_prefix(prefix.size());
|
|
|
|
if (in.starts_with("num-files-at-level")) {
|
|
in.remove_prefix(strlen("num-files-at-level"));
|
|
uint64_t level;
|
|
bool ok = ConsumeDecimalNumber(&in, &level) && in.empty();
|
|
if (!ok || (int)level >= NumberLevels()) {
|
|
return false;
|
|
} else {
|
|
char buf[100];
|
|
snprintf(buf, sizeof(buf), "%d",
|
|
versions_->NumLevelFiles(static_cast<int>(level)));
|
|
*value = buf;
|
|
return true;
|
|
}
|
|
} else if (in == "stats") {
|
|
char buf[1000];
|
|
uint64_t total_bytes = 0;
|
|
uint64_t micros_up = env_->NowMicros() - started_at_;
|
|
double seconds_up = micros_up / 1000000.0;
|
|
|
|
// Pardon the long line but I think it is easier to read this way.
|
|
snprintf(buf, sizeof(buf),
|
|
" Compactions\n"
|
|
"Level Files Size(MB) Time(sec) Read(MB) Write(MB) Rn(MB) Rnp1(MB) Wnew(MB) Amplify Read(MB/s) Write(MB/s) Rn Rnp1 Wnp1 NewW Count\n"
|
|
"------------------------------------------------------------------------------------------------------------------------------------------------------------\n"
|
|
);
|
|
value->append(buf);
|
|
for (int level = 0; level < NumberLevels(); level++) {
|
|
int files = versions_->NumLevelFiles(level);
|
|
if (stats_[level].micros > 0 || files > 0) {
|
|
int64_t bytes_read = stats_[level].bytes_readn +
|
|
stats_[level].bytes_readnp1;
|
|
int64_t bytes_new = stats_[level].bytes_written -
|
|
stats_[level].bytes_readnp1;
|
|
double amplify = (stats_[level].bytes_readn == 0)
|
|
? 0.0
|
|
: (stats_[level].bytes_written + stats_[level].bytes_readnp1) /
|
|
(double) stats_[level].bytes_readn;
|
|
|
|
total_bytes += bytes_read + stats_[level].bytes_written;
|
|
snprintf(
|
|
buf, sizeof(buf),
|
|
"%3d %8d %8.0f %9.0f %9.0f %9.0f %9.0f %9.0f %9.0f %7.1f %9.1f %11.1f %8d %8d %8d %8d %8d\n",
|
|
level,
|
|
files,
|
|
versions_->NumLevelBytes(level) / 1048576.0,
|
|
stats_[level].micros / 1e6,
|
|
bytes_read / 1048576.0,
|
|
stats_[level].bytes_written / 1048576.0,
|
|
stats_[level].bytes_readn / 1048576.0,
|
|
stats_[level].bytes_readnp1 / 1048576.0,
|
|
bytes_new / 1048576.0,
|
|
amplify,
|
|
(bytes_read / 1048576.0) / (stats_[level].micros / 1000000.0),
|
|
(stats_[level].bytes_written / 1048576.0) /
|
|
(stats_[level].micros / 1000000.0),
|
|
stats_[level].files_in_leveln,
|
|
stats_[level].files_in_levelnp1,
|
|
stats_[level].files_out_levelnp1,
|
|
stats_[level].files_out_levelnp1 - stats_[level].files_in_levelnp1,
|
|
stats_[level].count);
|
|
value->append(buf);
|
|
}
|
|
}
|
|
|
|
snprintf(buf, sizeof(buf),
|
|
"Amplification: %.1f rate, %.2f GB in, %.2f GB out, %.2f MB/sec in, %.2f MB/sec out\n",
|
|
(double) total_bytes / stats_[0].bytes_written,
|
|
stats_[0].bytes_written / (1048576.0 * 1024),
|
|
total_bytes / (1048576.0 * 1024),
|
|
stats_[0].bytes_written / 1048576.0 / seconds_up,
|
|
total_bytes / 1048576.0 / seconds_up);
|
|
value->append(buf);
|
|
|
|
snprintf(buf, sizeof(buf), "Uptime(secs): %.1f\n", seconds_up);
|
|
value->append(buf);
|
|
|
|
snprintf(buf, sizeof(buf),
|
|
"Stalls(secs): %.3f level0_slowdown, %.3f level0_numfiles, "
|
|
"%.3f memtable_compaction, %.3f leveln_slowdown\n",
|
|
stall_level0_slowdown_ / 1000000.0,
|
|
stall_level0_num_files_ / 1000000.0,
|
|
stall_memtable_compaction_ / 1000000.0,
|
|
stall_leveln_slowdown_ / 1000000.0);
|
|
value->append(buf);
|
|
|
|
return true;
|
|
} else if (in == "sstables") {
|
|
*value = versions_->current()->DebugString();
|
|
return true;
|
|
}
|
|
|
|
return false;
|
|
}
|
|
|
|
void DBImpl::GetApproximateSizes(
|
|
const Range* range, int n,
|
|
uint64_t* sizes) {
|
|
// TODO(opt): better implementation
|
|
Version* v;
|
|
{
|
|
MutexLock l(&mutex_);
|
|
versions_->current()->Ref();
|
|
v = versions_->current();
|
|
}
|
|
|
|
for (int i = 0; i < n; i++) {
|
|
// Convert user_key into a corresponding internal key.
|
|
InternalKey k1(range[i].start, kMaxSequenceNumber, kValueTypeForSeek);
|
|
InternalKey k2(range[i].limit, kMaxSequenceNumber, kValueTypeForSeek);
|
|
uint64_t start = versions_->ApproximateOffsetOf(v, k1);
|
|
uint64_t limit = versions_->ApproximateOffsetOf(v, k2);
|
|
sizes[i] = (limit >= start ? limit - start : 0);
|
|
}
|
|
|
|
{
|
|
MutexLock l(&mutex_);
|
|
v->Unref();
|
|
}
|
|
}
|
|
|
|
// Default implementations of convenience methods that subclasses of DB
|
|
// can call if they wish
|
|
Status DB::Put(const WriteOptions& opt, const Slice& key, const Slice& value) {
|
|
WriteBatch batch;
|
|
batch.Put(key, value);
|
|
return Write(opt, &batch);
|
|
}
|
|
|
|
Status DB::Delete(const WriteOptions& opt, const Slice& key) {
|
|
WriteBatch batch;
|
|
batch.Delete(key);
|
|
return Write(opt, &batch);
|
|
}
|
|
|
|
DB::~DB() { }
|
|
|
|
Status DB::Open(const Options& options, const std::string& dbname,
|
|
DB** dbptr) {
|
|
*dbptr = NULL;
|
|
|
|
DBImpl* impl = new DBImpl(options, dbname);
|
|
impl->mutex_.Lock();
|
|
VersionEdit edit(impl->NumberLevels());
|
|
Status s = impl->Recover(&edit); // Handles create_if_missing, error_if_exists
|
|
if (s.ok()) {
|
|
uint64_t new_log_number = impl->versions_->NewFileNumber();
|
|
WritableFile* lfile;
|
|
s = options.env->NewWritableFile(LogFileName(dbname, new_log_number),
|
|
&lfile);
|
|
if (s.ok()) {
|
|
edit.SetLogNumber(new_log_number);
|
|
impl->logfile_ = lfile;
|
|
impl->logfile_number_ = new_log_number;
|
|
impl->log_ = new log::Writer(lfile);
|
|
s = impl->versions_->LogAndApply(&edit, &impl->mutex_);
|
|
}
|
|
if (s.ok()) {
|
|
impl->DeleteObsoleteFiles();
|
|
impl->MaybeScheduleCompaction();
|
|
impl->MaybeScheduleLogDBDeployStats();
|
|
}
|
|
}
|
|
impl->mutex_.Unlock();
|
|
if (s.ok()) {
|
|
*dbptr = impl;
|
|
} else {
|
|
delete impl;
|
|
}
|
|
return s;
|
|
}
|
|
|
|
Snapshot::~Snapshot() {
|
|
}
|
|
|
|
Status DestroyDB(const std::string& dbname, const Options& options) {
|
|
Env* env = options.env;
|
|
std::vector<std::string> filenames;
|
|
// Ignore error in case directory does not exist
|
|
env->GetChildren(dbname, &filenames);
|
|
if (filenames.empty()) {
|
|
return Status::OK();
|
|
}
|
|
|
|
FileLock* lock;
|
|
const std::string lockname = LockFileName(dbname);
|
|
Status result = env->LockFile(lockname, &lock);
|
|
if (result.ok()) {
|
|
uint64_t number;
|
|
FileType type;
|
|
for (size_t i = 0; i < filenames.size(); i++) {
|
|
if (ParseFileName(filenames[i], &number, &type) &&
|
|
type != kDBLockFile) { // Lock file will be deleted at end
|
|
Status del = env->DeleteFile(dbname + "/" + filenames[i]);
|
|
if (result.ok() && !del.ok()) {
|
|
result = del;
|
|
}
|
|
}
|
|
}
|
|
env->UnlockFile(lock); // Ignore error since state is already gone
|
|
env->DeleteFile(lockname);
|
|
env->DeleteDir(dbname); // Ignore error in case dir contains other files
|
|
}
|
|
return result;
|
|
}
|
|
|
|
//
|
|
// A global method that can dump out the build version
|
|
void dumpLeveldbBuildVersion(Logger * log) {
|
|
Log(log, "Git sha %s", leveldb_build_git_sha);
|
|
Log(log, "Git datetime %s", leveldb_build_git_datetime);
|
|
Log(log, "Compile time %s %s", leveldb_build_compile_time, leveldb_build_compile_date);
|
|
}
|
|
|
|
} // namespace leveldb
|