rocksdb/db/column_family.cc
Igor Canadi 8cb7ad83c3 Flush stale column families less aggressively
Summary:
We've seen some production issues where column family is detected as stale, although there is only one column family in the system. This is a quick fix that:
1) doesn't flush stale column families if there's only one of them
2) Use 4 as a coefficient instead of 2 for determening when a column family is stale. This will make flushing less aggressive, while still keep a nice dynamic flushing of very stale CFs.

Test Plan: make check

Reviewers: dhruba, haobo, ljin, sdong

Reviewed By: sdong

Subscribers: leveldb

Differential Revision: https://reviews.facebook.net/D18861
2014-06-02 15:33:54 -07:00

605 lines
20 KiB
C++

// Copyright (c) 2013, Facebook, Inc. All rights reserved.
// This source code is licensed under the BSD-style license found in the
// LICENSE file in the root directory of this source tree. An additional grant
// of patent rights can be found in the PATENTS file in the same 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.
#include "db/column_family.h"
#include <vector>
#include <string>
#include <algorithm>
#include <limits>
#include "db/db_impl.h"
#include "db/version_set.h"
#include "db/internal_stats.h"
#include "db/compaction_picker.h"
#include "db/table_properties_collector.h"
#include "util/autovector.h"
#include "util/hash_skiplist_rep.h"
namespace rocksdb {
ColumnFamilyHandleImpl::ColumnFamilyHandleImpl(ColumnFamilyData* cfd,
DBImpl* db, port::Mutex* mutex)
: cfd_(cfd), db_(db), mutex_(mutex) {
if (cfd_ != nullptr) {
cfd_->Ref();
}
}
ColumnFamilyHandleImpl::~ColumnFamilyHandleImpl() {
if (cfd_ != nullptr) {
DBImpl::DeletionState deletion_state;
mutex_->Lock();
if (cfd_->Unref()) {
delete cfd_;
}
db_->FindObsoleteFiles(deletion_state, false, true);
mutex_->Unlock();
if (deletion_state.HaveSomethingToDelete()) {
db_->PurgeObsoleteFiles(deletion_state);
}
}
}
uint32_t ColumnFamilyHandleImpl::GetID() const { return cfd()->GetID(); }
namespace {
// Fix user-supplied options to be reasonable
template <class T, class V>
static void ClipToRange(T* ptr, V minvalue, V maxvalue) {
if (static_cast<V>(*ptr) > maxvalue) *ptr = maxvalue;
if (static_cast<V>(*ptr) < minvalue) *ptr = minvalue;
}
} // anonymous namespace
ColumnFamilyOptions SanitizeOptions(const InternalKeyComparator* icmp,
const InternalFilterPolicy* ipolicy,
const ColumnFamilyOptions& src) {
ColumnFamilyOptions result = src;
result.comparator = icmp;
result.filter_policy = (src.filter_policy != nullptr) ? ipolicy : nullptr;
#ifdef OS_MACOSX
// TODO(icanadi) make write_buffer_size uint64_t instead of size_t
ClipToRange(&result.write_buffer_size, ((size_t)64) << 10, ((size_t)1) << 30);
#else
ClipToRange(&result.write_buffer_size,
((size_t)64) << 10, ((size_t)64) << 30);
#endif
// if user sets arena_block_size, we trust user to use this value. Otherwise,
// calculate a proper value from writer_buffer_size;
if (result.arena_block_size <= 0) {
result.arena_block_size = result.write_buffer_size / 10;
}
result.min_write_buffer_number_to_merge =
std::min(result.min_write_buffer_number_to_merge,
result.max_write_buffer_number - 1);
if (result.block_cache == nullptr && !result.no_block_cache) {
result.block_cache = NewLRUCache(8 << 20);
}
result.compression_per_level = src.compression_per_level;
if (result.block_size_deviation < 0 || result.block_size_deviation > 100) {
result.block_size_deviation = 0;
}
if (result.max_mem_compaction_level >= result.num_levels) {
result.max_mem_compaction_level = result.num_levels - 1;
}
if (result.soft_rate_limit > result.hard_rate_limit) {
result.soft_rate_limit = result.hard_rate_limit;
}
if (!result.prefix_extractor) {
assert(result.memtable_factory);
Slice name = result.memtable_factory->Name();
if (name.compare("HashSkipListRepFactory") == 0 ||
name.compare("HashLinkListRepFactory") == 0) {
result.memtable_factory = std::make_shared<SkipListFactory>();
}
}
// -- Sanitize the table properties collector
// All user defined properties collectors will be wrapped by
// UserKeyTablePropertiesCollector since for them they only have the
// knowledge of the user keys; internal keys are invisible to them.
auto& collector_factories = result.table_properties_collector_factories;
for (size_t i = 0; i < result.table_properties_collector_factories.size();
++i) {
assert(collector_factories[i]);
collector_factories[i] =
std::make_shared<UserKeyTablePropertiesCollectorFactory>(
collector_factories[i]);
}
// Add collector to collect internal key statistics
collector_factories.push_back(
std::make_shared<InternalKeyPropertiesCollectorFactory>());
if (result.compaction_style == kCompactionStyleFIFO) {
result.num_levels = 1;
// since we delete level0 files in FIFO compaction when there are too many
// of them, these options don't really mean anything
result.level0_file_num_compaction_trigger = std::numeric_limits<int>::max();
result.level0_slowdown_writes_trigger = std::numeric_limits<int>::max();
result.level0_stop_writes_trigger = std::numeric_limits<int>::max();
}
return result;
}
int SuperVersion::dummy = 0;
void* const SuperVersion::kSVInUse = &SuperVersion::dummy;
void* const SuperVersion::kSVObsolete = nullptr;
SuperVersion::~SuperVersion() {
for (auto td : to_delete) {
delete td;
}
}
SuperVersion* SuperVersion::Ref() {
refs.fetch_add(1, std::memory_order_relaxed);
return this;
}
bool SuperVersion::Unref() {
// fetch_sub returns the previous value of ref
uint32_t previous_refs = refs.fetch_sub(1, std::memory_order_relaxed);
assert(previous_refs > 0);
return previous_refs == 1;
}
void SuperVersion::Cleanup() {
assert(refs.load(std::memory_order_relaxed) == 0);
imm->Unref(&to_delete);
MemTable* m = mem->Unref();
if (m != nullptr) {
to_delete.push_back(m);
}
current->Unref();
}
void SuperVersion::Init(MemTable* new_mem, MemTableListVersion* new_imm,
Version* new_current) {
mem = new_mem;
imm = new_imm;
current = new_current;
mem->Ref();
imm->Ref();
current->Ref();
refs.store(1, std::memory_order_relaxed);
}
namespace {
void SuperVersionUnrefHandle(void* ptr) {
// UnrefHandle is called when a thread exists or a ThreadLocalPtr gets
// destroyed. When former happens, the thread shouldn't see kSVInUse.
// When latter happens, we are in ~ColumnFamilyData(), no get should happen as
// well.
SuperVersion* sv = static_cast<SuperVersion*>(ptr);
if (sv->Unref()) {
sv->db_mutex->Lock();
sv->Cleanup();
sv->db_mutex->Unlock();
delete sv;
}
}
} // anonymous namespace
ColumnFamilyData::ColumnFamilyData(const std::string& dbname, uint32_t id,
const std::string& name,
Version* dummy_versions, Cache* table_cache,
const ColumnFamilyOptions& options,
const DBOptions* db_options,
const EnvOptions& storage_options,
ColumnFamilySet* column_family_set)
: id_(id),
name_(name),
dummy_versions_(dummy_versions),
current_(nullptr),
refs_(0),
dropped_(false),
internal_comparator_(options.comparator),
internal_filter_policy_(options.filter_policy),
options_(*db_options, SanitizeOptions(&internal_comparator_,
&internal_filter_policy_, options)),
mem_(nullptr),
imm_(options_.min_write_buffer_number_to_merge),
super_version_(nullptr),
super_version_number_(0),
local_sv_(new ThreadLocalPtr(&SuperVersionUnrefHandle)),
next_(nullptr),
prev_(nullptr),
log_number_(0),
need_slowdown_for_num_level0_files_(false),
column_family_set_(column_family_set) {
Ref();
// if dummy_versions is nullptr, then this is a dummy column family.
if (dummy_versions != nullptr) {
internal_stats_.reset(new InternalStats(
options_.num_levels, db_options->env, db_options->statistics.get()));
table_cache_.reset(
new TableCache(dbname, &options_, storage_options, table_cache));
if (options_.compaction_style == kCompactionStyleUniversal) {
compaction_picker_.reset(
new UniversalCompactionPicker(&options_, &internal_comparator_));
} else if (options_.compaction_style == kCompactionStyleLevel) {
compaction_picker_.reset(
new LevelCompactionPicker(&options_, &internal_comparator_));
} else {
assert(options_.compaction_style == kCompactionStyleFIFO);
compaction_picker_.reset(
new FIFOCompactionPicker(&options_, &internal_comparator_));
}
Log(options_.info_log, "Options for column family \"%s\":\n",
name.c_str());
const ColumnFamilyOptions* cf_options = &options_;
cf_options->Dump(options_.info_log.get());
}
}
// DB mutex held
ColumnFamilyData::~ColumnFamilyData() {
assert(refs_ == 0);
// remove from linked list
auto prev = prev_;
auto next = next_;
prev->next_ = next;
next->prev_ = prev;
// it's nullptr for dummy CFD
if (column_family_set_ != nullptr) {
// remove from column_family_set
column_family_set_->RemoveColumnFamily(this);
}
if (current_ != nullptr) {
current_->Unref();
}
if (super_version_ != nullptr) {
// Release SuperVersion reference kept in ThreadLocalPtr.
// This must be done outside of mutex_ since unref handler can lock mutex.
super_version_->db_mutex->Unlock();
local_sv_.reset();
super_version_->db_mutex->Lock();
bool is_last_reference __attribute__((unused));
is_last_reference = super_version_->Unref();
assert(is_last_reference);
super_version_->Cleanup();
delete super_version_;
super_version_ = nullptr;
}
if (dummy_versions_ != nullptr) {
// List must be empty
assert(dummy_versions_->next_ == dummy_versions_);
delete dummy_versions_;
}
if (mem_ != nullptr) {
delete mem_->Unref();
}
autovector<MemTable*> to_delete;
imm_.current()->Unref(&to_delete);
for (MemTable* m : to_delete) {
delete m;
}
}
const EnvOptions* ColumnFamilyData::soptions() const {
return &(column_family_set_->storage_options_);
}
void ColumnFamilyData::SetCurrent(Version* current) {
current_ = current;
need_slowdown_for_num_level0_files_ =
(options_.level0_slowdown_writes_trigger >= 0 &&
current_->NumLevelFiles(0) >= options_.level0_slowdown_writes_trigger);
}
void ColumnFamilyData::CreateNewMemtable() {
assert(current_ != nullptr);
if (mem_ != nullptr) {
delete mem_->Unref();
}
mem_ = new MemTable(internal_comparator_, options_);
mem_->Ref();
}
Compaction* ColumnFamilyData::PickCompaction(LogBuffer* log_buffer) {
return compaction_picker_->PickCompaction(current_, log_buffer);
}
Compaction* ColumnFamilyData::CompactRange(int input_level, int output_level,
const InternalKey* begin,
const InternalKey* end,
InternalKey** compaction_end) {
return compaction_picker_->CompactRange(current_, input_level, output_level,
begin, end, compaction_end);
}
SuperVersion* ColumnFamilyData::GetReferencedSuperVersion(
port::Mutex* db_mutex) {
SuperVersion* sv = nullptr;
if (LIKELY(column_family_set_->db_options_->allow_thread_local)) {
sv = GetThreadLocalSuperVersion(db_mutex);
sv->Ref();
if (!ReturnThreadLocalSuperVersion(sv)) {
sv->Unref();
}
} else {
db_mutex->Lock();
sv = super_version_->Ref();
db_mutex->Unlock();
}
return sv;
}
SuperVersion* ColumnFamilyData::GetThreadLocalSuperVersion(
port::Mutex* db_mutex) {
SuperVersion* sv = nullptr;
// The SuperVersion is cached in thread local storage to avoid acquiring
// mutex when SuperVersion does not change since the last use. When a new
// SuperVersion is installed, the compaction or flush thread cleans up
// cached SuperVersion in all existing thread local storage. To avoid
// acquiring mutex for this operation, we use atomic Swap() on the thread
// local pointer to guarantee exclusive access. If the thread local pointer
// is being used while a new SuperVersion is installed, the cached
// SuperVersion can become stale. In that case, the background thread would
// have swapped in kSVObsolete. We re-check the value at when returning
// SuperVersion back to thread local, with an atomic compare and swap.
// The superversion will need to be released if detected to be stale.
void* ptr = local_sv_->Swap(SuperVersion::kSVInUse);
// Invariant:
// (1) Scrape (always) installs kSVObsolete in ThreadLocal storage
// (2) the Swap above (always) installs kSVInUse, ThreadLocal storage
// should only keep kSVInUse before ReturnThreadLocalSuperVersion call
// (if no Scrape happens).
assert(ptr != SuperVersion::kSVInUse);
sv = static_cast<SuperVersion*>(ptr);
if (sv == SuperVersion::kSVObsolete ||
sv->version_number != super_version_number_.load()) {
RecordTick(options_.statistics.get(), NUMBER_SUPERVERSION_ACQUIRES);
SuperVersion* sv_to_delete = nullptr;
if (sv && sv->Unref()) {
RecordTick(options_.statistics.get(), NUMBER_SUPERVERSION_CLEANUPS);
db_mutex->Lock();
// NOTE: underlying resources held by superversion (sst files) might
// not be released until the next background job.
sv->Cleanup();
sv_to_delete = sv;
} else {
db_mutex->Lock();
}
sv = super_version_->Ref();
db_mutex->Unlock();
delete sv_to_delete;
}
assert(sv != nullptr);
return sv;
}
bool ColumnFamilyData::ReturnThreadLocalSuperVersion(SuperVersion* sv) {
assert(sv != nullptr);
// Put the SuperVersion back
void* expected = SuperVersion::kSVInUse;
if (local_sv_->CompareAndSwap(static_cast<void*>(sv), expected)) {
// When we see kSVInUse in the ThreadLocal, we are sure ThreadLocal
// storage has not been altered and no Scrape has happend. The
// SuperVersion is still current.
return true;
} else {
// ThreadLocal scrape happened in the process of this GetImpl call (after
// thread local Swap() at the beginning and before CompareAndSwap()).
// This means the SuperVersion it holds is obsolete.
assert(expected == SuperVersion::kSVObsolete);
}
return false;
}
SuperVersion* ColumnFamilyData::InstallSuperVersion(
SuperVersion* new_superversion, port::Mutex* db_mutex) {
new_superversion->db_mutex = db_mutex;
new_superversion->Init(mem_, imm_.current(), current_);
SuperVersion* old_superversion = super_version_;
super_version_ = new_superversion;
++super_version_number_;
super_version_->version_number = super_version_number_;
// Reset SuperVersions cached in thread local storage
if (column_family_set_->db_options_->allow_thread_local) {
ResetThreadLocalSuperVersions();
}
if (old_superversion != nullptr && old_superversion->Unref()) {
old_superversion->Cleanup();
return old_superversion; // will let caller delete outside of mutex
}
return nullptr;
}
void ColumnFamilyData::ResetThreadLocalSuperVersions() {
autovector<void*> sv_ptrs;
local_sv_->Scrape(&sv_ptrs, SuperVersion::kSVObsolete);
for (auto ptr : sv_ptrs) {
assert(ptr);
if (ptr == SuperVersion::kSVInUse) {
continue;
}
auto sv = static_cast<SuperVersion*>(ptr);
if (sv->Unref()) {
sv->Cleanup();
delete sv;
}
}
}
ColumnFamilySet::ColumnFamilySet(const std::string& dbname,
const DBOptions* db_options,
const EnvOptions& storage_options,
Cache* table_cache)
: max_column_family_(0),
dummy_cfd_(new ColumnFamilyData(dbname, 0, "", nullptr, nullptr,
ColumnFamilyOptions(), db_options,
storage_options_, nullptr)),
default_cfd_cache_(nullptr),
db_name_(dbname),
db_options_(db_options),
storage_options_(storage_options),
table_cache_(table_cache),
spin_lock_(ATOMIC_FLAG_INIT) {
// initialize linked list
dummy_cfd_->prev_ = dummy_cfd_;
dummy_cfd_->next_ = dummy_cfd_;
}
ColumnFamilySet::~ColumnFamilySet() {
while (column_family_data_.size() > 0) {
// cfd destructor will delete itself from column_family_data_
auto cfd = column_family_data_.begin()->second;
cfd->Unref();
delete cfd;
}
dummy_cfd_->Unref();
delete dummy_cfd_;
}
ColumnFamilyData* ColumnFamilySet::GetDefault() const {
assert(default_cfd_cache_ != nullptr);
return default_cfd_cache_;
}
ColumnFamilyData* ColumnFamilySet::GetColumnFamily(uint32_t id) const {
auto cfd_iter = column_family_data_.find(id);
if (cfd_iter != column_family_data_.end()) {
return cfd_iter->second;
} else {
return nullptr;
}
}
ColumnFamilyData* ColumnFamilySet::GetColumnFamily(const std::string& name)
const {
auto cfd_iter = column_families_.find(name);
if (cfd_iter != column_families_.end()) {
auto cfd = GetColumnFamily(cfd_iter->second);
assert(cfd != nullptr);
return cfd;
} else {
return nullptr;
}
}
uint32_t ColumnFamilySet::GetNextColumnFamilyID() {
return ++max_column_family_;
}
uint32_t ColumnFamilySet::GetMaxColumnFamily() { return max_column_family_; }
void ColumnFamilySet::UpdateMaxColumnFamily(uint32_t new_max_column_family) {
max_column_family_ = std::max(new_max_column_family, max_column_family_);
}
size_t ColumnFamilySet::NumberOfColumnFamilies() const {
return column_families_.size();
}
// under a DB mutex
ColumnFamilyData* ColumnFamilySet::CreateColumnFamily(
const std::string& name, uint32_t id, Version* dummy_versions,
const ColumnFamilyOptions& options) {
assert(column_families_.find(name) == column_families_.end());
ColumnFamilyData* new_cfd =
new ColumnFamilyData(db_name_, id, name, dummy_versions, table_cache_,
options, db_options_, storage_options_, this);
Lock();
column_families_.insert({name, id});
column_family_data_.insert({id, new_cfd});
Unlock();
max_column_family_ = std::max(max_column_family_, id);
// add to linked list
new_cfd->next_ = dummy_cfd_;
auto prev = dummy_cfd_->prev_;
new_cfd->prev_ = prev;
prev->next_ = new_cfd;
dummy_cfd_->prev_ = new_cfd;
if (id == 0) {
default_cfd_cache_ = new_cfd;
}
return new_cfd;
}
void ColumnFamilySet::Lock() {
// spin lock
while (spin_lock_.test_and_set(std::memory_order_acquire)) {
}
}
void ColumnFamilySet::Unlock() { spin_lock_.clear(std::memory_order_release); }
// REQUIRES: DB mutex held
void ColumnFamilySet::FreeDeadColumnFamilies() {
autovector<ColumnFamilyData*> to_delete;
for (auto cfd = dummy_cfd_->next_; cfd != dummy_cfd_; cfd = cfd->next_) {
if (cfd->refs_ == 0) {
to_delete.push_back(cfd);
}
}
for (auto cfd : to_delete) {
// this is very rare, so it's not a problem that we do it under a mutex
delete cfd;
}
}
// under a DB mutex
void ColumnFamilySet::RemoveColumnFamily(ColumnFamilyData* cfd) {
auto cfd_iter = column_family_data_.find(cfd->GetID());
assert(cfd_iter != column_family_data_.end());
Lock();
column_family_data_.erase(cfd_iter);
column_families_.erase(cfd->GetName());
Unlock();
}
bool ColumnFamilyMemTablesImpl::Seek(uint32_t column_family_id) {
if (column_family_id == 0) {
// optimization for common case
current_ = column_family_set_->GetDefault();
} else {
// maybe outside of db mutex, should lock
column_family_set_->Lock();
current_ = column_family_set_->GetColumnFamily(column_family_id);
column_family_set_->Unlock();
}
handle_.SetCFD(current_);
return current_ != nullptr;
}
uint64_t ColumnFamilyMemTablesImpl::GetLogNumber() const {
assert(current_ != nullptr);
return current_->GetLogNumber();
}
MemTable* ColumnFamilyMemTablesImpl::GetMemTable() const {
assert(current_ != nullptr);
return current_->mem();
}
const Options* ColumnFamilyMemTablesImpl::GetOptions() const {
assert(current_ != nullptr);
return current_->options();
}
ColumnFamilyHandle* ColumnFamilyMemTablesImpl::GetColumnFamilyHandle() {
assert(current_ != nullptr);
return &handle_;
}
} // namespace rocksdb