fork of https://github.com/oxigraph/rocksdb and https://github.com/facebook/rocksdb for nextgraph and oxigraph
You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
532 lines
18 KiB
532 lines
18 KiB
// 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/memtable.h"
|
|
|
|
#include <memory>
|
|
|
|
#include "db/dbformat.h"
|
|
#include "db/merge_context.h"
|
|
#include "rocksdb/comparator.h"
|
|
#include "rocksdb/env.h"
|
|
#include "rocksdb/iterator.h"
|
|
#include "rocksdb/merge_operator.h"
|
|
#include "rocksdb/slice_transform.h"
|
|
#include "util/arena.h"
|
|
#include "util/coding.h"
|
|
#include "util/murmurhash.h"
|
|
#include "util/mutexlock.h"
|
|
#include "util/perf_context_imp.h"
|
|
#include "util/statistics.h"
|
|
#include "util/stop_watch.h"
|
|
|
|
namespace std {
|
|
template <>
|
|
struct hash<rocksdb::Slice> {
|
|
size_t operator()(const rocksdb::Slice& slice) const {
|
|
return MurmurHash(slice.data(), slice.size(), 0);
|
|
}
|
|
};
|
|
}
|
|
|
|
namespace rocksdb {
|
|
|
|
MemTable::MemTable(const InternalKeyComparator& cmp,
|
|
const ColumnFamilyOptions& options)
|
|
: comparator_(cmp),
|
|
refs_(0),
|
|
arena_(options.arena_block_size),
|
|
table_(options.memtable_factory->CreateMemTableRep(comparator_, &arena_)),
|
|
flush_in_progress_(false),
|
|
flush_completed_(false),
|
|
file_number_(0),
|
|
first_seqno_(0),
|
|
mem_next_logfile_number_(0),
|
|
mem_logfile_number_(0),
|
|
locks_(options.inplace_update_support ? options.inplace_update_num_locks
|
|
: 0),
|
|
prefix_extractor_(options.prefix_extractor) {
|
|
if (prefix_extractor_ && options.memtable_prefix_bloom_bits > 0) {
|
|
prefix_bloom_.reset(new DynamicBloom(options.memtable_prefix_bloom_bits,
|
|
options.memtable_prefix_bloom_probes));
|
|
}
|
|
}
|
|
|
|
MemTable::~MemTable() {
|
|
assert(refs_ == 0);
|
|
}
|
|
|
|
size_t MemTable::ApproximateMemoryUsage() {
|
|
return arena_.ApproximateMemoryUsage() + table_->ApproximateMemoryUsage();
|
|
}
|
|
|
|
int MemTable::KeyComparator::operator()(const char* prefix_len_key1,
|
|
const char* prefix_len_key2) const {
|
|
// Internal keys are encoded as length-prefixed strings.
|
|
Slice k1 = GetLengthPrefixedSlice(prefix_len_key1);
|
|
Slice k2 = GetLengthPrefixedSlice(prefix_len_key2);
|
|
return comparator.Compare(k1, k2);
|
|
}
|
|
|
|
int MemTable::KeyComparator::operator()(const char* prefix_len_key,
|
|
const Slice& key)
|
|
const {
|
|
// Internal keys are encoded as length-prefixed strings.
|
|
Slice a = GetLengthPrefixedSlice(prefix_len_key);
|
|
return comparator.Compare(a, key);
|
|
}
|
|
|
|
Slice MemTableRep::UserKey(const char* key) const {
|
|
Slice slice = GetLengthPrefixedSlice(key);
|
|
return Slice(slice.data(), slice.size() - 8);
|
|
}
|
|
|
|
// Encode a suitable internal key target for "target" and return it.
|
|
// Uses *scratch as scratch space, and the returned pointer will point
|
|
// into this scratch space.
|
|
const char* EncodeKey(std::string* scratch, const Slice& target) {
|
|
scratch->clear();
|
|
PutVarint32(scratch, target.size());
|
|
scratch->append(target.data(), target.size());
|
|
return scratch->data();
|
|
}
|
|
|
|
class MemTableIterator: public Iterator {
|
|
public:
|
|
MemTableIterator(const MemTable& mem, const ReadOptions& options)
|
|
: mem_(mem), iter_(), dynamic_prefix_seek_(false), valid_(false) {
|
|
if (options.prefix) {
|
|
iter_.reset(mem_.table_->GetPrefixIterator(*options.prefix));
|
|
} else if (options.prefix_seek) {
|
|
dynamic_prefix_seek_ = true;
|
|
iter_.reset(mem_.table_->GetDynamicPrefixIterator());
|
|
} else {
|
|
iter_.reset(mem_.table_->GetIterator());
|
|
}
|
|
}
|
|
|
|
virtual bool Valid() const { return valid_; }
|
|
virtual void Seek(const Slice& k) {
|
|
if (dynamic_prefix_seek_ && mem_.prefix_bloom_ &&
|
|
!mem_.prefix_bloom_->MayContain(
|
|
mem_.prefix_extractor_->Transform(ExtractUserKey(k)))) {
|
|
valid_ = false;
|
|
return;
|
|
}
|
|
iter_->Seek(k, nullptr);
|
|
valid_ = iter_->Valid();
|
|
}
|
|
virtual void SeekToFirst() {
|
|
iter_->SeekToFirst();
|
|
valid_ = iter_->Valid();
|
|
}
|
|
virtual void SeekToLast() {
|
|
iter_->SeekToLast();
|
|
valid_ = iter_->Valid();
|
|
}
|
|
virtual void Next() {
|
|
assert(Valid());
|
|
iter_->Next();
|
|
valid_ = iter_->Valid();
|
|
}
|
|
virtual void Prev() {
|
|
assert(Valid());
|
|
iter_->Prev();
|
|
valid_ = iter_->Valid();
|
|
}
|
|
virtual Slice key() const {
|
|
assert(Valid());
|
|
return GetLengthPrefixedSlice(iter_->key());
|
|
}
|
|
virtual Slice value() const {
|
|
assert(Valid());
|
|
Slice key_slice = GetLengthPrefixedSlice(iter_->key());
|
|
return GetLengthPrefixedSlice(key_slice.data() + key_slice.size());
|
|
}
|
|
|
|
virtual Status status() const { return Status::OK(); }
|
|
|
|
private:
|
|
const MemTable& mem_;
|
|
std::shared_ptr<MemTableRep::Iterator> iter_;
|
|
bool dynamic_prefix_seek_;
|
|
bool valid_;
|
|
|
|
// No copying allowed
|
|
MemTableIterator(const MemTableIterator&);
|
|
void operator=(const MemTableIterator&);
|
|
};
|
|
|
|
Iterator* MemTable::NewIterator(const ReadOptions& options) {
|
|
return new MemTableIterator(*this, options);
|
|
}
|
|
|
|
port::RWMutex* MemTable::GetLock(const Slice& key) {
|
|
return &locks_[std::hash<Slice>()(key) % locks_.size()];
|
|
}
|
|
|
|
void MemTable::Add(SequenceNumber s, ValueType type,
|
|
const Slice& key, /* user key */
|
|
const Slice& value) {
|
|
// Format of an entry is concatenation of:
|
|
// key_size : varint32 of internal_key.size()
|
|
// key bytes : char[internal_key.size()]
|
|
// value_size : varint32 of value.size()
|
|
// value bytes : char[value.size()]
|
|
size_t key_size = key.size();
|
|
size_t val_size = value.size();
|
|
size_t internal_key_size = key_size + 8;
|
|
const size_t encoded_len =
|
|
VarintLength(internal_key_size) + internal_key_size +
|
|
VarintLength(val_size) + val_size;
|
|
char* buf = arena_.Allocate(encoded_len);
|
|
char* p = EncodeVarint32(buf, internal_key_size);
|
|
memcpy(p, key.data(), key_size);
|
|
p += key_size;
|
|
EncodeFixed64(p, (s << 8) | type);
|
|
p += 8;
|
|
p = EncodeVarint32(p, val_size);
|
|
memcpy(p, value.data(), val_size);
|
|
assert((unsigned)(p + val_size - buf) == (unsigned)encoded_len);
|
|
table_->Insert(buf);
|
|
|
|
if (prefix_bloom_) {
|
|
assert(prefix_extractor_);
|
|
prefix_bloom_->Add(prefix_extractor_->Transform(key));
|
|
}
|
|
|
|
// The first sequence number inserted into the memtable
|
|
assert(first_seqno_ == 0 || s > first_seqno_);
|
|
if (first_seqno_ == 0) {
|
|
first_seqno_ = s;
|
|
}
|
|
}
|
|
|
|
// Callback from MemTable::Get()
|
|
namespace {
|
|
|
|
struct Saver {
|
|
Status* status;
|
|
const LookupKey* key;
|
|
bool* found_final_value; // Is value set correctly? Used by KeyMayExist
|
|
bool* merge_in_progress;
|
|
std::string* value;
|
|
const MergeOperator* merge_operator;
|
|
// the merge operations encountered;
|
|
MergeContext* merge_context;
|
|
MemTable* mem;
|
|
Logger* logger;
|
|
Statistics* statistics;
|
|
bool inplace_update_support;
|
|
};
|
|
} // namespace
|
|
|
|
static bool SaveValue(void* arg, const char* entry) {
|
|
Saver* s = reinterpret_cast<Saver*>(arg);
|
|
MergeContext* merge_context = s->merge_context;
|
|
const MergeOperator* merge_operator = s->merge_operator;
|
|
|
|
assert(s != nullptr && merge_context != nullptr);
|
|
|
|
// entry format is:
|
|
// klength varint32
|
|
// userkey char[klength-8]
|
|
// tag uint64
|
|
// vlength varint32
|
|
// value char[vlength]
|
|
// Check that it belongs to same user key. We do not check the
|
|
// sequence number since the Seek() call above should have skipped
|
|
// all entries with overly large sequence numbers.
|
|
uint32_t key_length;
|
|
const char* key_ptr = GetVarint32Ptr(entry, entry + 5, &key_length);
|
|
if (s->mem->GetInternalKeyComparator().user_comparator()->Compare(
|
|
Slice(key_ptr, key_length - 8), s->key->user_key()) == 0) {
|
|
// Correct user key
|
|
const uint64_t tag = DecodeFixed64(key_ptr + key_length - 8);
|
|
switch (static_cast<ValueType>(tag & 0xff)) {
|
|
case kTypeValue: {
|
|
if (s->inplace_update_support) {
|
|
s->mem->GetLock(s->key->user_key())->ReadLock();
|
|
}
|
|
Slice v = GetLengthPrefixedSlice(key_ptr + key_length);
|
|
*(s->status) = Status::OK();
|
|
if (*(s->merge_in_progress)) {
|
|
assert(merge_operator);
|
|
if (!merge_operator->FullMerge(s->key->user_key(), &v,
|
|
merge_context->GetOperands(), s->value,
|
|
s->logger)) {
|
|
RecordTick(s->statistics, NUMBER_MERGE_FAILURES);
|
|
*(s->status) =
|
|
Status::Corruption("Error: Could not perform merge.");
|
|
}
|
|
} else {
|
|
s->value->assign(v.data(), v.size());
|
|
}
|
|
if (s->inplace_update_support) {
|
|
s->mem->GetLock(s->key->user_key())->Unlock();
|
|
}
|
|
*(s->found_final_value) = true;
|
|
return false;
|
|
}
|
|
case kTypeDeletion: {
|
|
if (*(s->merge_in_progress)) {
|
|
assert(merge_operator);
|
|
*(s->status) = Status::OK();
|
|
if (!merge_operator->FullMerge(s->key->user_key(), nullptr,
|
|
merge_context->GetOperands(), s->value,
|
|
s->logger)) {
|
|
RecordTick(s->statistics, NUMBER_MERGE_FAILURES);
|
|
*(s->status) =
|
|
Status::Corruption("Error: Could not perform merge.");
|
|
}
|
|
} else {
|
|
*(s->status) = Status::NotFound();
|
|
}
|
|
*(s->found_final_value) = true;
|
|
return false;
|
|
}
|
|
case kTypeMerge: {
|
|
std::string merge_result; // temporary area for merge results later
|
|
Slice v = GetLengthPrefixedSlice(key_ptr + key_length);
|
|
*(s->merge_in_progress) = true;
|
|
merge_context->PushOperand(v);
|
|
while (merge_context->GetNumOperands() >= 2) {
|
|
// Attempt to associative merge. (Returns true if successful)
|
|
if (merge_operator->PartialMerge(
|
|
s->key->user_key(), merge_context->GetOperand(0),
|
|
merge_context->GetOperand(1), &merge_result, s->logger)) {
|
|
merge_context->PushPartialMergeResult(merge_result);
|
|
} else {
|
|
// Stack them because user can't associative merge
|
|
break;
|
|
}
|
|
}
|
|
return true;
|
|
}
|
|
default:
|
|
assert(false);
|
|
return true;
|
|
}
|
|
}
|
|
|
|
// s->state could be Corrupt, merge or notfound
|
|
return false;
|
|
}
|
|
|
|
bool MemTable::Get(const LookupKey& key, std::string* value, Status* s,
|
|
MergeContext& merge_context, const Options& options) {
|
|
StopWatchNano memtable_get_timer(options.env, false);
|
|
StartPerfTimer(&memtable_get_timer);
|
|
|
|
Slice user_key = key.user_key();
|
|
bool found_final_value = false;
|
|
bool merge_in_progress = s->IsMergeInProgress();
|
|
|
|
if (prefix_bloom_ &&
|
|
!prefix_bloom_->MayContain(prefix_extractor_->Transform(user_key))) {
|
|
// iter is null if prefix bloom says the key does not exist
|
|
} else {
|
|
Saver saver;
|
|
saver.status = s;
|
|
saver.found_final_value = &found_final_value;
|
|
saver.merge_in_progress = &merge_in_progress;
|
|
saver.key = &key;
|
|
saver.value = value;
|
|
saver.status = s;
|
|
saver.mem = this;
|
|
saver.merge_context = &merge_context;
|
|
saver.merge_operator = options.merge_operator.get();
|
|
saver.logger = options.info_log.get();
|
|
saver.inplace_update_support = options.inplace_update_support;
|
|
saver.statistics = options.statistics.get();
|
|
table_->Get(key, &saver, SaveValue);
|
|
}
|
|
|
|
// No change to value, since we have not yet found a Put/Delete
|
|
if (!found_final_value && merge_in_progress) {
|
|
*s = Status::MergeInProgress("");
|
|
}
|
|
BumpPerfTime(&perf_context.get_from_memtable_time, &memtable_get_timer);
|
|
BumpPerfCount(&perf_context.get_from_memtable_count);
|
|
return found_final_value;
|
|
}
|
|
|
|
void MemTable::Update(SequenceNumber seq,
|
|
const Slice& key,
|
|
const Slice& value) {
|
|
LookupKey lkey(key, seq);
|
|
Slice mem_key = lkey.memtable_key();
|
|
|
|
std::unique_ptr<MemTableRep::Iterator> iter(
|
|
table_->GetIterator(lkey.user_key()));
|
|
iter->Seek(lkey.internal_key(), mem_key.data());
|
|
|
|
if (iter->Valid()) {
|
|
// entry format is:
|
|
// key_length varint32
|
|
// userkey char[klength-8]
|
|
// tag uint64
|
|
// vlength varint32
|
|
// value char[vlength]
|
|
// Check that it belongs to same user key. We do not check the
|
|
// sequence number since the Seek() call above should have skipped
|
|
// all entries with overly large sequence numbers.
|
|
const char* entry = iter->key();
|
|
uint32_t key_length = 0;
|
|
const char* key_ptr = GetVarint32Ptr(entry, entry + 5, &key_length);
|
|
if (comparator_.comparator.user_comparator()->Compare(
|
|
Slice(key_ptr, key_length - 8), lkey.user_key()) == 0) {
|
|
// Correct user key
|
|
const uint64_t tag = DecodeFixed64(key_ptr + key_length - 8);
|
|
switch (static_cast<ValueType>(tag & 0xff)) {
|
|
case kTypeValue: {
|
|
Slice prev_value = GetLengthPrefixedSlice(key_ptr + key_length);
|
|
uint32_t prev_size = prev_value.size();
|
|
uint32_t new_size = value.size();
|
|
|
|
// Update value, if new value size <= previous value size
|
|
if (new_size <= prev_size ) {
|
|
char* p = EncodeVarint32(const_cast<char*>(key_ptr) + key_length,
|
|
new_size);
|
|
WriteLock wl(GetLock(lkey.user_key()));
|
|
memcpy(p, value.data(), value.size());
|
|
assert((unsigned)((p + value.size()) - entry) ==
|
|
(unsigned)(VarintLength(key_length) + key_length +
|
|
VarintLength(value.size()) + value.size()));
|
|
return;
|
|
}
|
|
}
|
|
default:
|
|
// If the latest value is kTypeDeletion, kTypeMerge or kTypeLogData
|
|
// we don't have enough space for update inplace
|
|
Add(seq, kTypeValue, key, value);
|
|
return;
|
|
}
|
|
}
|
|
}
|
|
|
|
// key doesn't exist
|
|
Add(seq, kTypeValue, key, value);
|
|
}
|
|
|
|
bool MemTable::UpdateCallback(SequenceNumber seq,
|
|
const Slice& key,
|
|
const Slice& delta,
|
|
const Options& options) {
|
|
LookupKey lkey(key, seq);
|
|
Slice memkey = lkey.memtable_key();
|
|
|
|
std::shared_ptr<MemTableRep::Iterator> iter(
|
|
table_->GetIterator(lkey.user_key()));
|
|
iter->Seek(lkey.internal_key(), memkey.data());
|
|
|
|
if (iter->Valid()) {
|
|
// entry format is:
|
|
// key_length varint32
|
|
// userkey char[klength-8]
|
|
// tag uint64
|
|
// vlength varint32
|
|
// value char[vlength]
|
|
// Check that it belongs to same user key. We do not check the
|
|
// sequence number since the Seek() call above should have skipped
|
|
// all entries with overly large sequence numbers.
|
|
const char* entry = iter->key();
|
|
uint32_t key_length = 0;
|
|
const char* key_ptr = GetVarint32Ptr(entry, entry + 5, &key_length);
|
|
if (comparator_.comparator.user_comparator()->Compare(
|
|
Slice(key_ptr, key_length - 8), lkey.user_key()) == 0) {
|
|
// Correct user key
|
|
const uint64_t tag = DecodeFixed64(key_ptr + key_length - 8);
|
|
switch (static_cast<ValueType>(tag & 0xff)) {
|
|
case kTypeValue: {
|
|
Slice prev_value = GetLengthPrefixedSlice(key_ptr + key_length);
|
|
uint32_t prev_size = prev_value.size();
|
|
|
|
char* prev_buffer = const_cast<char*>(prev_value.data());
|
|
uint32_t new_prev_size = prev_size;
|
|
|
|
std::string str_value;
|
|
WriteLock wl(GetLock(lkey.user_key()));
|
|
auto status = options.inplace_callback(prev_buffer, &new_prev_size,
|
|
delta, &str_value);
|
|
if (status == UpdateStatus::UPDATED_INPLACE) {
|
|
// Value already updated by callback.
|
|
assert(new_prev_size <= prev_size);
|
|
if (new_prev_size < prev_size) {
|
|
// overwrite the new prev_size
|
|
char* p = EncodeVarint32(const_cast<char*>(key_ptr) + key_length,
|
|
new_prev_size);
|
|
if (VarintLength(new_prev_size) < VarintLength(prev_size)) {
|
|
// shift the value buffer as well.
|
|
memcpy(p, prev_buffer, new_prev_size);
|
|
}
|
|
}
|
|
RecordTick(options.statistics.get(), NUMBER_KEYS_UPDATED);
|
|
return true;
|
|
} else if (status == UpdateStatus::UPDATED) {
|
|
Add(seq, kTypeValue, key, Slice(str_value));
|
|
RecordTick(options.statistics.get(), NUMBER_KEYS_WRITTEN);
|
|
return true;
|
|
} else if (status == UpdateStatus::UPDATE_FAILED) {
|
|
// No action required. Return.
|
|
return true;
|
|
}
|
|
}
|
|
default:
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
// If the latest value is not kTypeValue
|
|
// or key doesn't exist
|
|
return false;
|
|
}
|
|
|
|
size_t MemTable::CountSuccessiveMergeEntries(const LookupKey& key) {
|
|
Slice memkey = key.memtable_key();
|
|
|
|
// A total ordered iterator is costly for some memtablerep (prefix aware
|
|
// reps). By passing in the user key, we allow efficient iterator creation.
|
|
// The iterator only needs to be ordered within the same user key.
|
|
std::unique_ptr<MemTableRep::Iterator> iter(
|
|
table_->GetIterator(key.user_key()));
|
|
iter->Seek(key.internal_key(), memkey.data());
|
|
|
|
size_t num_successive_merges = 0;
|
|
|
|
for (; iter->Valid(); iter->Next()) {
|
|
const char* entry = iter->key();
|
|
uint32_t key_length = 0;
|
|
const char* iter_key_ptr = GetVarint32Ptr(entry, entry + 5, &key_length);
|
|
if (!comparator_.comparator.user_comparator()->Compare(
|
|
Slice(iter_key_ptr, key_length - 8), key.user_key()) == 0) {
|
|
break;
|
|
}
|
|
|
|
const uint64_t tag = DecodeFixed64(iter_key_ptr + key_length - 8);
|
|
if (static_cast<ValueType>(tag & 0xff) != kTypeMerge) {
|
|
break;
|
|
}
|
|
|
|
++num_successive_merges;
|
|
}
|
|
|
|
return num_successive_merges;
|
|
}
|
|
|
|
void MemTableRep::Get(const LookupKey& k, void* callback_args,
|
|
bool (*callback_func)(void* arg, const char* entry)) {
|
|
auto iter = GetIterator(k.user_key());
|
|
for (iter->Seek(k.internal_key(), k.memtable_key().data());
|
|
iter->Valid() && callback_func(callback_args, iter->key());
|
|
iter->Next()) {
|
|
}
|
|
}
|
|
|
|
} // namespace rocksdb
|
|
|