rocksdb/db/job_context.h

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// Copyright (c) 2011-present, Facebook, Inc. All rights reserved.
// This source code is licensed under both the GPLv2 (found in the
// COPYING file in the root directory) and Apache 2.0 License
// (found in the LICENSE.Apache file in the root directory).
//
// Copyright (c) 2011 The LevelDB Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file. See the AUTHORS file for names of contributors.
#pragma once
#include <string>
#include <vector>
#include "db/log_writer.h"
#include "db/column_family.h"
namespace rocksdb {
class MemTable;
struct SuperVersion;
struct SuperVersionContext {
struct WriteStallNotification {
WriteStallInfo write_stall_info;
const ImmutableCFOptions* immutable_cf_options;
};
autovector<SuperVersion*> superversions_to_free;
#ifndef ROCKSDB_DISABLE_STALL_NOTIFICATION
autovector<WriteStallNotification> write_stall_notifications;
#endif
std::unique_ptr<SuperVersion>
new_superversion; // if nullptr no new superversion
explicit SuperVersionContext(bool create_superversion = false)
: new_superversion(create_superversion ? new SuperVersion() : nullptr) {}
explicit SuperVersionContext(SuperVersionContext&& other)
: superversions_to_free(std::move(other.superversions_to_free)),
#ifndef ROCKSDB_DISABLE_STALL_NOTIFICATION
write_stall_notifications(std::move(other.write_stall_notifications)),
#endif
new_superversion(std::move(other.new_superversion)) {
}
void NewSuperVersion() {
new_superversion = std::unique_ptr<SuperVersion>(new SuperVersion());
}
inline bool HaveSomethingToDelete() const {
#ifndef ROCKSDB_DISABLE_STALL_NOTIFICATION
return !superversions_to_free.empty() ||
!write_stall_notifications.empty();
#else
return !superversions_to_free.empty();
#endif
}
void PushWriteStallNotification(
WriteStallCondition old_cond, WriteStallCondition new_cond,
const std::string& name, const ImmutableCFOptions* ioptions) {
#if !defined(ROCKSDB_LITE) && !defined(ROCKSDB_DISABLE_STALL_NOTIFICATION)
WriteStallNotification notif;
notif.write_stall_info.cf_name = name;
notif.write_stall_info.condition.prev = old_cond;
notif.write_stall_info.condition.cur = new_cond;
notif.immutable_cf_options = ioptions;
write_stall_notifications.push_back(notif);
#else
(void)old_cond;
(void)new_cond;
(void)name;
(void)ioptions;
#endif // !defined(ROCKSDB_LITE) && !defined(ROCKSDB_DISABLE_STALL_NOTIFICATION)
}
void Clean() {
#if !defined(ROCKSDB_LITE) && !defined(ROCKSDB_DISABLE_STALL_NOTIFICATION)
// notify listeners on changed write stall conditions
for (auto& notif : write_stall_notifications) {
for (auto& listener : notif.immutable_cf_options->listeners) {
listener->OnStallConditionsChanged(notif.write_stall_info);
}
}
write_stall_notifications.clear();
#endif // !ROCKSDB_LITE
// free superversions
for (auto s : superversions_to_free) {
delete s;
}
superversions_to_free.clear();
}
~SuperVersionContext() {
#ifndef ROCKSDB_DISABLE_STALL_NOTIFICATION
assert(write_stall_notifications.empty());
#endif
assert(superversions_to_free.empty());
}
};
struct JobContext {
inline bool HaveSomethingToDelete() const {
Speed up FindObsoleteFiles() Summary: There are two versions of FindObsoleteFiles(): * full scan, which is executed every 6 hours (and it's terribly slow) * no full scan, which is executed every time a background process finishes and iterator is deleted This diff is optimizing the second case (no full scan). Here's what we do before the diff: * Get the list of obsolete files (files with ref==0). Some files in obsolete_files set might actually be live. * Get the list of live files to avoid deleting files that are live. * Delete files that are in obsolete_files and not in live_files. After this diff: * The only files with ref==0 that are still live are files that have been part of move compaction. Don't include moved files in obsolete_files. * Get the list of obsolete files (which exclude moved files). * No need to get the list of live files, since all files in obsolete_files need to be deleted. I'll post the benchmark results, but you can get the feel of it here: https://reviews.facebook.net/D30123 This depends on D30123. P.S. We should do full scan only in failure scenarios, not every 6 hours. I'll do this in a follow-up diff. Test Plan: One new unit test. Made sure that unit test fails if we don't have a `if (!f->moved)` safeguard in ~Version. make check Big number of compactions and flushes: ./db_stress --threads=30 --ops_per_thread=20000000 --max_key=10000 --column_families=20 --clear_column_family_one_in=10000000 --verify_before_write=0 --reopen=15 --max_background_compactions=10 --max_background_flushes=10 --db=/fast-rocksdb-tmp/db_stress --prefixpercent=0 --iterpercent=0 --writepercent=75 --db_write_buffer_size=2000000 Reviewers: yhchiang, rven, sdong Reviewed By: sdong Subscribers: dhruba, leveldb Differential Revision: https://reviews.facebook.net/D30249
2014-12-22 12:04:45 +01:00
return full_scan_candidate_files.size() || sst_delete_files.size() ||
log_delete_files.size() || manifest_delete_files.size();
}
inline bool HaveSomethingToClean() const {
bool sv_have_sth = false;
for (const auto& sv_ctx : superversion_contexts) {
if (sv_ctx.HaveSomethingToDelete()) {
sv_have_sth = true;
break;
}
}
return memtables_to_free.size() > 0 || logs_to_free.size() > 0 ||
sv_have_sth;
}
// Structure to store information for candidate files to delete.
struct CandidateFileInfo {
std::string file_name;
std::string file_path;
CandidateFileInfo(std::string name, std::string path)
: file_name(std::move(name)), file_path(std::move(path)) {}
bool operator==(const CandidateFileInfo& other) const {
return file_name == other.file_name &&
file_path == other.file_path;
}
};
// Unique job id
int job_id;
// a list of all files that we'll consider deleting
// (every once in a while this is filled up with all files
// in the DB directory)
Speed up FindObsoleteFiles() Summary: There are two versions of FindObsoleteFiles(): * full scan, which is executed every 6 hours (and it's terribly slow) * no full scan, which is executed every time a background process finishes and iterator is deleted This diff is optimizing the second case (no full scan). Here's what we do before the diff: * Get the list of obsolete files (files with ref==0). Some files in obsolete_files set might actually be live. * Get the list of live files to avoid deleting files that are live. * Delete files that are in obsolete_files and not in live_files. After this diff: * The only files with ref==0 that are still live are files that have been part of move compaction. Don't include moved files in obsolete_files. * Get the list of obsolete files (which exclude moved files). * No need to get the list of live files, since all files in obsolete_files need to be deleted. I'll post the benchmark results, but you can get the feel of it here: https://reviews.facebook.net/D30123 This depends on D30123. P.S. We should do full scan only in failure scenarios, not every 6 hours. I'll do this in a follow-up diff. Test Plan: One new unit test. Made sure that unit test fails if we don't have a `if (!f->moved)` safeguard in ~Version. make check Big number of compactions and flushes: ./db_stress --threads=30 --ops_per_thread=20000000 --max_key=10000 --column_families=20 --clear_column_family_one_in=10000000 --verify_before_write=0 --reopen=15 --max_background_compactions=10 --max_background_flushes=10 --db=/fast-rocksdb-tmp/db_stress --prefixpercent=0 --iterpercent=0 --writepercent=75 --db_write_buffer_size=2000000 Reviewers: yhchiang, rven, sdong Reviewed By: sdong Subscribers: dhruba, leveldb Differential Revision: https://reviews.facebook.net/D30249
2014-12-22 12:04:45 +01:00
// (filled only if we're doing full scan)
std::vector<CandidateFileInfo> full_scan_candidate_files;
// the list of all live sst files that cannot be deleted
std::vector<FileDescriptor> sst_live;
// a list of sst files that we need to delete
std::vector<ObsoleteFileInfo> sst_delete_files;
// a list of log files that we need to delete
std::vector<uint64_t> log_delete_files;
// a list of log files that we need to preserve during full purge since they
// will be reused later
std::vector<uint64_t> log_recycle_files;
// a list of manifest files that we need to delete
std::vector<std::string> manifest_delete_files;
// a list of memtables to be free
autovector<MemTable*> memtables_to_free;
// contexts for installing superversions for multiple column families
std::vector<SuperVersionContext> superversion_contexts;
autovector<log::Writer*> logs_to_free;
// the current manifest_file_number, log_number and prev_log_number
// that corresponds to the set of files in 'live'.
uint64_t manifest_file_number;
uint64_t pending_manifest_file_number;
uint64_t log_number;
uint64_t prev_log_number;
uint64_t min_pending_output = 0;
uint64_t prev_total_log_size = 0;
size_t num_alive_log_files = 0;
uint64_t size_log_to_delete = 0;
explicit JobContext(int _job_id, bool create_superversion = false) {
job_id = _job_id;
manifest_file_number = 0;
pending_manifest_file_number = 0;
log_number = 0;
prev_log_number = 0;
superversion_contexts.emplace_back(
SuperVersionContext(create_superversion));
}
// For non-empty JobContext Clean() has to be called at least once before
// before destruction (see asserts in ~JobContext()). Should be called with
// unlocked DB mutex. Destructor doesn't call Clean() to avoid accidentally
// doing potentially slow Clean() with locked DB mutex.
void Clean() {
// free superversions
for (auto& sv_context : superversion_contexts) {
sv_context.Clean();
}
// free pending memtables
for (auto m : memtables_to_free) {
delete m;
}
for (auto l : logs_to_free) {
delete l;
}
memtables_to_free.clear();
logs_to_free.clear();
}
~JobContext() {
assert(memtables_to_free.size() == 0);
assert(logs_to_free.size() == 0);
}
};
} // namespace rocksdb