rocksdb/db/column_family.cc
Igor Canadi 7731d51c82 Simplify column family concurrency
Summary:
This patch changes concurrency guarantees around ColumnFamilySet::column_families_ and ColumnFamilySet::column_families_data_.

Before:
* When mutating: lock DB mutex and spin lock
* When reading: lock DB mutex OR spin lock

After:
* When mutating: lock DB mutex and be in write thread
* When reading: lock DB mutex or be in write thread

That way, we eliminate the spin lock that protects these hash maps and  simplify concurrency. That means we don't need to lock the spin lock during writing, since writing is mutually exclusive with column family create/drop (the only operations that mutate those hash maps).

With these new restrictions, I also needed to move column family create to the write thread (column family drop was already in the write thread).

Even though we don't need to lock the spin lock during write, impact on performance should be minimal -- the spin lock is almost never busy, so locking it is almost free.

This addresses task t5116919.

Test Plan:
make check

Stress test with lots and lots of column family drop and create:

   time ./db_stress --threads=30 --ops_per_thread=5000000 --max_key=5000 --column_families=200 --clear_column_family_one_in=100000 --verify_before_write=0  --reopen=15 --max_background_compactions=10 --max_background_flushes=10 --db=/fast-rocksdb-tmp/db_stress/

Reviewers: yhchiang, rven, sdong

Reviewed By: sdong

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D30651
2015-01-06 12:44:21 -08:00

805 lines
27 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"
#ifndef __STDC_FORMAT_MACROS
#define __STDC_FORMAT_MACROS
#endif
#include <inttypes.h>
#include <vector>
#include <string>
#include <algorithm>
#include <limits>
#include "db/compaction_picker.h"
#include "db/db_impl.h"
#include "db/job_context.h"
#include "db/version_set.h"
#include "db/writebuffer.h"
#include "db/internal_stats.h"
#include "db/job_context.h"
#include "db/table_properties_collector.h"
#include "db/version_set.h"
#include "db/write_controller.h"
#include "util/autovector.h"
#include "util/hash_skiplist_rep.h"
#include "util/options_helper.h"
namespace rocksdb {
namespace {
// This function computes the amount of time in microseconds by which a write
// should be delayed based on the number of level-0 files according to the
// following formula:
// if n < bottom, return 0;
// if n >= top, return 1000;
// otherwise, let r = (n - bottom) /
// (top - bottom)
// and return r^2 * 1000.
// The goal of this formula is to gradually increase the rate at which writes
// are slowed. We also tried linear delay (r * 1000), but it seemed to do
// slightly worse. There is no other particular reason for choosing quadratic.
uint64_t SlowdownAmount(int n, double bottom, double top) {
uint64_t delay;
if (n >= top) {
delay = 1000;
} else if (n < bottom) {
delay = 0;
} else {
// If we are here, we know that:
// level0_start_slowdown <= n < level0_slowdown
// since the previous two conditions are false.
double how_much = static_cast<double>(n - bottom) / (top - bottom);
delay = std::max(how_much * how_much * 1000, 100.0);
}
assert(delay <= 1000);
return delay;
}
} // namespace
ColumnFamilyHandleImpl::ColumnFamilyHandleImpl(
ColumnFamilyData* column_family_data, DBImpl* db, port::Mutex* mutex)
: cfd_(column_family_data), db_(db), mutex_(mutex) {
if (cfd_ != nullptr) {
cfd_->Ref();
}
}
ColumnFamilyHandleImpl::~ColumnFamilyHandleImpl() {
if (cfd_ != nullptr) {
JobContext job_context;
mutex_->Lock();
if (cfd_->Unref()) {
delete cfd_;
}
db_->FindObsoleteFiles(&job_context, false, true);
mutex_->Unlock();
if (job_context.HaveSomethingToDelete()) {
db_->PurgeObsoleteFiles(job_context);
}
}
}
uint32_t ColumnFamilyHandleImpl::GetID() const { return cfd()->GetID(); }
const std::string& ColumnFamilyHandleImpl::GetName() const {
return cfd()->GetName();
}
const Comparator* ColumnFamilyHandleImpl::user_comparator() const {
return cfd()->user_comparator();
}
ColumnFamilyOptions SanitizeOptions(const InternalKeyComparator* icmp,
const ColumnFamilyOptions& src) {
ColumnFamilyOptions result = src;
result.comparator = icmp;
#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);
result.compression_per_level = src.compression_per_level;
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.max_write_buffer_number < 2) {
result.max_write_buffer_number = 2;
}
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(
uint32_t id, const std::string& name, Version* _dummy_versions,
Cache* _table_cache, WriteBuffer* write_buffer,
const ColumnFamilyOptions& cf_options, const DBOptions* db_options,
const EnvOptions& env_options, ColumnFamilySet* column_family_set)
: id_(id),
name_(name),
dummy_versions_(_dummy_versions),
current_(nullptr),
refs_(0),
dropped_(false),
internal_comparator_(cf_options.comparator),
options_(*db_options, SanitizeOptions(&internal_comparator_, cf_options)),
ioptions_(options_),
mutable_cf_options_(options_, ioptions_),
write_buffer_(write_buffer),
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),
column_family_set_(column_family_set),
pending_flush_(false),
pending_compaction_(false) {
Ref();
// if _dummy_versions is nullptr, then this is a dummy column family.
if (_dummy_versions != nullptr) {
internal_stats_.reset(
new InternalStats(ioptions_.num_levels, db_options->env, this));
table_cache_.reset(new TableCache(ioptions_, env_options, _table_cache));
if (ioptions_.compaction_style == kCompactionStyleLevel) {
compaction_picker_.reset(
new LevelCompactionPicker(ioptions_, &internal_comparator_));
#ifndef ROCKSDB_LITE
} else if (ioptions_.compaction_style == kCompactionStyleUniversal) {
compaction_picker_.reset(
new UniversalCompactionPicker(ioptions_, &internal_comparator_));
} else if (ioptions_.compaction_style == kCompactionStyleFIFO) {
compaction_picker_.reset(
new FIFOCompactionPicker(ioptions_, &internal_comparator_));
} else if (ioptions_.compaction_style == kCompactionStyleNone) {
compaction_picker_.reset(new NullCompactionPicker(
ioptions_, &internal_comparator_));
Log(InfoLogLevel::WARN_LEVEL, ioptions_.info_log,
"Column family %s does not use any background compaction. "
"Compactions can only be done via CompactFiles\n",
GetName().c_str());
#endif // !ROCKSDB_LITE
} else {
Log(InfoLogLevel::ERROR_LEVEL, ioptions_.info_log,
"Unable to recognize the specified compaction style %d. "
"Column family %s will use kCompactionStyleLevel.\n",
ioptions_.compaction_style, GetName().c_str());
compaction_picker_.reset(
new LevelCompactionPicker(ioptions_, &internal_comparator_));
}
if (column_family_set_->NumberOfColumnFamilies() < 10) {
Log(InfoLogLevel::INFO_LEVEL, ioptions_.info_log,
"--------------- Options for column family [%s]:\n", name.c_str());
options_.Dump(ioptions_.info_log);
} else {
Log(InfoLogLevel::INFO_LEVEL, ioptions_.info_log,
"\t(skipping printing options)\n");
}
}
RecalculateWriteStallConditions(mutable_cf_options_);
}
// DB mutex held
ColumnFamilyData::~ColumnFamilyData() {
assert(refs_ == 0);
// remove from linked list
auto prev = prev_;
auto next = next_;
prev->next_ = next;
next->prev_ = prev;
if (!dropped_ && column_family_set_ != nullptr) {
// If it's dropped, it's already removed from column family set
// If column_family_set_ == nullptr, this is dummy CFD and not in
// ColumnFamilySet
column_family_set_->RemoveColumnFamily(this);
}
if (current_ != nullptr) {
current_->Unref();
}
// It would be wrong if this ColumnFamilyData is in flush_queue_ or
// compaction_queue_ and we destroyed it
assert(!pending_flush_);
assert(!pending_compaction_);
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_->TEST_Next() == dummy_versions_);
bool deleted __attribute__((unused)) = dummy_versions_->Unref();
assert(deleted);
}
if (mem_ != nullptr) {
delete mem_->Unref();
}
autovector<MemTable*> to_delete;
imm_.current()->Unref(&to_delete);
for (MemTable* m : to_delete) {
delete m;
}
}
void ColumnFamilyData::SetDropped() {
// can't drop default CF
assert(id_ != 0);
dropped_ = true;
write_controller_token_.reset();
// remove from column_family_set
column_family_set_->RemoveColumnFamily(this);
}
void ColumnFamilyData::RecalculateWriteStallConditions(
const MutableCFOptions& mutable_cf_options) {
if (current_ != nullptr) {
auto* vstorage = current_->storage_info();
const double score = vstorage->max_compaction_score();
const int max_level = vstorage->max_compaction_score_level();
auto write_controller = column_family_set_->write_controller_;
if (imm()->size() >= mutable_cf_options.max_write_buffer_number) {
write_controller_token_ = write_controller->GetStopToken();
internal_stats_->AddCFStats(InternalStats::MEMTABLE_COMPACTION, 1);
Log(InfoLogLevel::WARN_LEVEL, ioptions_.info_log,
"[%s] Stopping writes because we have %d immutable memtables "
"(waiting for flush), max_write_buffer_number is set to %d",
name_.c_str(), imm()->size(),
mutable_cf_options.max_write_buffer_number);
} else if (vstorage->NumLevelFiles(0) >=
mutable_cf_options.level0_stop_writes_trigger) {
write_controller_token_ = write_controller->GetStopToken();
internal_stats_->AddCFStats(InternalStats::LEVEL0_NUM_FILES, 1);
Log(InfoLogLevel::WARN_LEVEL, ioptions_.info_log,
"[%s] Stopping writes because we have %d level-0 files",
name_.c_str(), vstorage->NumLevelFiles(0));
} else if (mutable_cf_options.level0_slowdown_writes_trigger >= 0 &&
vstorage->NumLevelFiles(0) >=
mutable_cf_options.level0_slowdown_writes_trigger) {
uint64_t slowdown =
SlowdownAmount(vstorage->NumLevelFiles(0),
mutable_cf_options.level0_slowdown_writes_trigger,
mutable_cf_options.level0_stop_writes_trigger);
write_controller_token_ = write_controller->GetDelayToken(slowdown);
internal_stats_->AddCFStats(InternalStats::LEVEL0_SLOWDOWN, slowdown);
Log(InfoLogLevel::WARN_LEVEL, ioptions_.info_log,
"[%s] Stalling writes because we have %d level-0 files (%" PRIu64
"us)",
name_.c_str(), vstorage->NumLevelFiles(0), slowdown);
} else if (mutable_cf_options.hard_rate_limit > 1.0 &&
score > mutable_cf_options.hard_rate_limit) {
uint64_t kHardLimitSlowdown = 1000;
write_controller_token_ =
write_controller->GetDelayToken(kHardLimitSlowdown);
internal_stats_->RecordLevelNSlowdown(max_level, kHardLimitSlowdown,
false);
Log(InfoLogLevel::WARN_LEVEL, ioptions_.info_log,
"[%s] Stalling writes because we hit hard limit on level %d. "
"(%" PRIu64 "us)",
name_.c_str(), max_level, kHardLimitSlowdown);
} else if (mutable_cf_options.soft_rate_limit > 0.0 &&
score > mutable_cf_options.soft_rate_limit) {
uint64_t slowdown = SlowdownAmount(score,
mutable_cf_options.soft_rate_limit,
mutable_cf_options.hard_rate_limit);
write_controller_token_ = write_controller->GetDelayToken(slowdown);
internal_stats_->RecordLevelNSlowdown(max_level, slowdown, true);
Log(InfoLogLevel::WARN_LEVEL, ioptions_.info_log,
"[%s] Stalling writes because we hit soft limit on level %d (%" PRIu64
"us)",
name_.c_str(), max_level, slowdown);
} else {
write_controller_token_.reset();
}
}
}
const EnvOptions* ColumnFamilyData::soptions() const {
return &(column_family_set_->env_options_);
}
void ColumnFamilyData::SetCurrent(Version* current_version) {
current_ = current_version;
}
MemTable* ColumnFamilyData::ConstructNewMemtable(
const MutableCFOptions& mutable_cf_options) {
assert(current_ != nullptr);
return new MemTable(internal_comparator_, ioptions_,
mutable_cf_options, write_buffer_);
}
void ColumnFamilyData::CreateNewMemtable(
const MutableCFOptions& mutable_cf_options) {
if (mem_ != nullptr) {
delete mem_->Unref();
}
SetMemtable(ConstructNewMemtable(mutable_cf_options));
mem_->Ref();
}
bool ColumnFamilyData::NeedsCompaction() const {
return compaction_picker_->NeedsCompaction(current_->storage_info());
}
Compaction* ColumnFamilyData::PickCompaction(
const MutableCFOptions& mutable_options, LogBuffer* log_buffer) {
auto* result = compaction_picker_->PickCompaction(
GetName(), mutable_options, current_->storage_info(), log_buffer);
if (result != nullptr) {
result->SetInputVersion(current_);
}
return result;
}
Compaction* ColumnFamilyData::CompactRange(
const MutableCFOptions& mutable_cf_options,
int input_level, int output_level, uint32_t output_path_id,
const InternalKey* begin, const InternalKey* end,
InternalKey** compaction_end) {
auto* result = compaction_picker_->CompactRange(
GetName(), mutable_cf_options, current_->storage_info(), input_level,
output_level, output_path_id, begin, end, compaction_end);
if (result != nullptr) {
result->SetInputVersion(current_);
}
return result;
}
SuperVersion* ColumnFamilyData::GetReferencedSuperVersion(
port::Mutex* db_mutex) {
SuperVersion* sv = nullptr;
sv = GetThreadLocalSuperVersion(db_mutex);
sv->Ref();
if (!ReturnThreadLocalSuperVersion(sv)) {
sv->Unref();
}
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(ioptions_.statistics, NUMBER_SUPERVERSION_ACQUIRES);
SuperVersion* sv_to_delete = nullptr;
if (sv && sv->Unref()) {
RecordTick(ioptions_.statistics, 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;
}
void ColumnFamilyData::NotifyOnFlushCompleted(
DB* db, const std::string& file_path,
bool triggered_flush_slowdown,
bool triggered_flush_stop) {
#ifndef ROCKSDB_LITE
auto listeners = ioptions()->listeners;
for (auto listener : listeners) {
listener->OnFlushCompleted(
db, GetName(), file_path,
// Use path 0 as fulled memtables are first flushed into path 0.
triggered_flush_slowdown, triggered_flush_stop);
}
#endif // ROCKSDB_LITE
}
SuperVersion* ColumnFamilyData::InstallSuperVersion(
SuperVersion* new_superversion, port::Mutex* db_mutex) {
db_mutex->AssertHeld();
return InstallSuperVersion(new_superversion, db_mutex, mutable_cf_options_);
}
SuperVersion* ColumnFamilyData::InstallSuperVersion(
SuperVersion* new_superversion, port::Mutex* db_mutex,
const MutableCFOptions& mutable_cf_options) {
new_superversion->db_mutex = db_mutex;
new_superversion->mutable_cf_options = mutable_cf_options;
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
ResetThreadLocalSuperVersions();
RecalculateWriteStallConditions(mutable_cf_options);
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;
}
}
}
#ifndef ROCKSDB_LITE
Status ColumnFamilyData::SetOptions(
const std::unordered_map<std::string, std::string>& options_map) {
MutableCFOptions new_mutable_cf_options;
Status s = GetMutableOptionsFromStrings(mutable_cf_options_, options_map,
&new_mutable_cf_options);
if (s.ok()) {
mutable_cf_options_ = new_mutable_cf_options;
mutable_cf_options_.RefreshDerivedOptions(ioptions_);
}
return s;
}
#endif // ROCKSDB_LITE
ColumnFamilySet::ColumnFamilySet(const std::string& dbname,
const DBOptions* db_options,
const EnvOptions& env_options,
Cache* table_cache,
WriteBuffer* write_buffer,
WriteController* write_controller)
: max_column_family_(0),
dummy_cfd_(new ColumnFamilyData(0, "", nullptr, nullptr, nullptr,
ColumnFamilyOptions(), db_options,
env_options, nullptr)),
default_cfd_cache_(nullptr),
db_name_(dbname),
db_options_(db_options),
env_options_(env_options),
table_cache_(table_cache),
write_buffer_(write_buffer),
write_controller_(write_controller) {
// 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 AND write thread
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(id, name, dummy_versions, table_cache_,
write_buffer_, options, db_options_,
env_options_, this);
column_families_.insert({name, id});
column_family_data_.insert({id, new_cfd});
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;
}
// 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 AND from a write thread
void ColumnFamilySet::RemoveColumnFamily(ColumnFamilyData* cfd) {
auto cfd_iter = column_family_data_.find(cfd->GetID());
assert(cfd_iter != column_family_data_.end());
column_family_data_.erase(cfd_iter);
column_families_.erase(cfd->GetName());
}
// under a DB mutex OR from a write thread
bool ColumnFamilyMemTablesImpl::Seek(uint32_t column_family_id) {
if (column_family_id == 0) {
// optimization for common case
current_ = column_family_set_->GetDefault();
} else {
current_ = column_family_set_->GetColumnFamily(column_family_id);
}
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();
}
ColumnFamilyHandle* ColumnFamilyMemTablesImpl::GetColumnFamilyHandle() {
assert(current_ != nullptr);
return &handle_;
}
void ColumnFamilyMemTablesImpl::CheckMemtableFull() {
if (current_ != nullptr && current_->mem()->ShouldScheduleFlush()) {
flush_scheduler_->ScheduleFlush(current_);
current_->mem()->MarkFlushScheduled();
}
}
uint32_t GetColumnFamilyID(ColumnFamilyHandle* column_family) {
uint32_t column_family_id = 0;
if (column_family != nullptr) {
auto cfh = reinterpret_cast<ColumnFamilyHandleImpl*>(column_family);
column_family_id = cfh->GetID();
}
return column_family_id;
}
const Comparator* GetColumnFamilyUserComparator(
ColumnFamilyHandle* column_family) {
if (column_family != nullptr) {
auto cfh = reinterpret_cast<ColumnFamilyHandleImpl*>(column_family);
return cfh->user_comparator();
}
return nullptr;
}
} // namespace rocksdb