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rocksdb/db/memtable.cc
Levi Tamasi 2ea109521f Revisit the interface of MergeHelper::TimedFullMerge(WithEntity) (#10932) 
Summary:
The patch refines/reworks `MergeHelper::TimedFullMerge(WithEntity)`
a bit in two ways. First, it eliminates the recently introduced `TimedFullMerge`
overload, which makes the responsibilities clearer by making sure the query
result (`value` for `Get`, `columns` for `GetEntity`) is set uniformly in
`SaveValue` and `GetContext`. Second, it changes the interface of
`TimedFullMergeWithEntity` so it exposes its result in a serialized form; this
is a more decoupled design which will come in handy when adding support
for `Merge` with wide-column entities to `DBIter`.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/10932

Test Plan: `make check`

Reviewed By: akankshamahajan15

Differential Revision: D41129399

Pulled By: ltamasi

fbshipit-source-id: 69d8da358c77d4fc7e8c40f4dafc2c129a710677
2022-11-09 12:54:05 -08:00

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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.
#include "db/memtable.h"
#include <algorithm>
#include <array>
#include <limits>
#include <memory>
#include "db/dbformat.h"
#include "db/kv_checksum.h"
#include "db/merge_context.h"
#include "db/merge_helper.h"
#include "db/pinned_iterators_manager.h"
#include "db/range_tombstone_fragmenter.h"
#include "db/read_callback.h"
#include "db/wide/wide_column_serialization.h"
#include "logging/logging.h"
#include "memory/arena.h"
#include "memory/memory_usage.h"
#include "monitoring/perf_context_imp.h"
#include "monitoring/statistics.h"
#include "port/lang.h"
#include "port/port.h"
#include "rocksdb/comparator.h"
#include "rocksdb/env.h"
#include "rocksdb/iterator.h"
#include "rocksdb/merge_operator.h"
#include "rocksdb/slice_transform.h"
#include "rocksdb/types.h"
#include "rocksdb/write_buffer_manager.h"
#include "table/internal_iterator.h"
#include "table/iterator_wrapper.h"
#include "table/merging_iterator.h"
#include "util/autovector.h"
#include "util/coding.h"
#include "util/mutexlock.h"
namespace ROCKSDB_NAMESPACE {
ImmutableMemTableOptions::ImmutableMemTableOptions(
const ImmutableOptions& ioptions,
const MutableCFOptions& mutable_cf_options)
: arena_block_size(mutable_cf_options.arena_block_size),
memtable_prefix_bloom_bits(
static_cast<uint32_t>(
static_cast<double>(mutable_cf_options.write_buffer_size) *
mutable_cf_options.memtable_prefix_bloom_size_ratio) *
8u),
memtable_huge_page_size(mutable_cf_options.memtable_huge_page_size),
memtable_whole_key_filtering(
mutable_cf_options.memtable_whole_key_filtering),
inplace_update_support(ioptions.inplace_update_support),
inplace_update_num_locks(mutable_cf_options.inplace_update_num_locks),
inplace_callback(ioptions.inplace_callback),
max_successive_merges(mutable_cf_options.max_successive_merges),
statistics(ioptions.stats),
merge_operator(ioptions.merge_operator.get()),
info_log(ioptions.logger),
allow_data_in_errors(ioptions.allow_data_in_errors),
protection_bytes_per_key(
mutable_cf_options.memtable_protection_bytes_per_key) {}
MemTable::MemTable(const InternalKeyComparator& cmp,
const ImmutableOptions& ioptions,
const MutableCFOptions& mutable_cf_options,
WriteBufferManager* write_buffer_manager,
SequenceNumber latest_seq, uint32_t column_family_id)
: comparator_(cmp),
moptions_(ioptions, mutable_cf_options),
refs_(0),
kArenaBlockSize(Arena::OptimizeBlockSize(moptions_.arena_block_size)),
mem_tracker_(write_buffer_manager),
arena_(moptions_.arena_block_size,
(write_buffer_manager != nullptr &&
(write_buffer_manager->enabled() ||
write_buffer_manager->cost_to_cache()))
? &mem_tracker_
: nullptr,
mutable_cf_options.memtable_huge_page_size),
table_(ioptions.memtable_factory->CreateMemTableRep(
comparator_, &arena_, mutable_cf_options.prefix_extractor.get(),
ioptions.logger, column_family_id)),
range_del_table_(SkipListFactory().CreateMemTableRep(
comparator_, &arena_, nullptr /* transform */, ioptions.logger,
column_family_id)),
is_range_del_table_empty_(true),
data_size_(0),
num_entries_(0),
num_deletes_(0),
write_buffer_size_(mutable_cf_options.write_buffer_size),
flush_in_progress_(false),
flush_completed_(false),
file_number_(0),
first_seqno_(0),
earliest_seqno_(latest_seq),
creation_seq_(latest_seq),
mem_next_logfile_number_(0),
min_prep_log_referenced_(0),
locks_(moptions_.inplace_update_support
? moptions_.inplace_update_num_locks
: 0),
prefix_extractor_(mutable_cf_options.prefix_extractor.get()),
flush_state_(FLUSH_NOT_REQUESTED),
clock_(ioptions.clock),
insert_with_hint_prefix_extractor_(
ioptions.memtable_insert_with_hint_prefix_extractor.get()),
oldest_key_time_(std::numeric_limits<uint64_t>::max()),
atomic_flush_seqno_(kMaxSequenceNumber),
approximate_memory_usage_(0) {
UpdateFlushState();
// something went wrong if we need to flush before inserting anything
assert(!ShouldScheduleFlush());
// use bloom_filter_ for both whole key and prefix bloom filter
if ((prefix_extractor_ || moptions_.memtable_whole_key_filtering) &&
moptions_.memtable_prefix_bloom_bits > 0) {
bloom_filter_.reset(
new DynamicBloom(&arena_, moptions_.memtable_prefix_bloom_bits,
6 /* hard coded 6 probes */,
moptions_.memtable_huge_page_size, ioptions.logger));
}
// Initialize cached_range_tombstone_ here since it could
// be read before it is constructed in MemTable::Add(), which could also lead
// to a data race on the global mutex table backing atomic shared_ptr.
auto new_cache = std::make_shared<FragmentedRangeTombstoneListCache>();
size_t size = cached_range_tombstone_.Size();
for (size_t i = 0; i < size; ++i) {
std::shared_ptr<FragmentedRangeTombstoneListCache>* local_cache_ref_ptr =
cached_range_tombstone_.AccessAtCore(i);
auto new_local_cache_ref = std::make_shared<
const std::shared_ptr<FragmentedRangeTombstoneListCache>>(new_cache);
std::atomic_store_explicit(
local_cache_ref_ptr,
std::shared_ptr<FragmentedRangeTombstoneListCache>(new_local_cache_ref,
new_cache.get()),
std::memory_order_relaxed);
}
}
MemTable::~MemTable() {
mem_tracker_.FreeMem();
assert(refs_ == 0);
}
size_t MemTable::ApproximateMemoryUsage() {
autovector<size_t> usages = {
arena_.ApproximateMemoryUsage(), table_->ApproximateMemoryUsage(),
range_del_table_->ApproximateMemoryUsage(),
ROCKSDB_NAMESPACE::ApproximateMemoryUsage(insert_hints_)};
size_t total_usage = 0;
for (size_t usage : usages) {
// If usage + total_usage >= kMaxSizet, return kMaxSizet.
// the following variation is to avoid numeric overflow.
if (usage >= std::numeric_limits<size_t>::max() - total_usage) {
return std::numeric_limits<size_t>::max();
}
total_usage += usage;
}
approximate_memory_usage_.store(total_usage, std::memory_order_relaxed);
// otherwise, return the actual usage
return total_usage;
}
bool MemTable::ShouldFlushNow() {
size_t write_buffer_size = write_buffer_size_.load(std::memory_order_relaxed);
// In a lot of times, we cannot allocate arena blocks that exactly matches the
// buffer size. Thus we have to decide if we should over-allocate or
// under-allocate.
// This constant variable can be interpreted as: if we still have more than
// "kAllowOverAllocationRatio * kArenaBlockSize" space left, we'd try to over
// allocate one more block.
const double kAllowOverAllocationRatio = 0.6;
// If arena still have room for new block allocation, we can safely say it
// shouldn't flush.
auto allocated_memory = table_->ApproximateMemoryUsage() +
range_del_table_->ApproximateMemoryUsage() +
arena_.MemoryAllocatedBytes();
approximate_memory_usage_.store(allocated_memory, std::memory_order_relaxed);
// if we can still allocate one more block without exceeding the
// over-allocation ratio, then we should not flush.
if (allocated_memory + kArenaBlockSize <
write_buffer_size + kArenaBlockSize * kAllowOverAllocationRatio) {
return false;
}
// if user keeps adding entries that exceeds write_buffer_size, we need to
// flush earlier even though we still have much available memory left.
if (allocated_memory >
write_buffer_size + kArenaBlockSize * kAllowOverAllocationRatio) {
return true;
}
// In this code path, Arena has already allocated its "last block", which
// means the total allocatedmemory size is either:
// (1) "moderately" over allocated the memory (no more than `0.6 * arena
// block size`. Or,
// (2) the allocated memory is less than write buffer size, but we'll stop
// here since if we allocate a new arena block, we'll over allocate too much
// more (half of the arena block size) memory.
//
// In either case, to avoid over-allocate, the last block will stop allocation
// when its usage reaches a certain ratio, which we carefully choose "0.75
// full" as the stop condition because it addresses the following issue with
// great simplicity: What if the next inserted entry's size is
// bigger than AllocatedAndUnused()?
//
// The answer is: if the entry size is also bigger than 0.25 *
// kArenaBlockSize, a dedicated block will be allocated for it; otherwise
// arena will anyway skip the AllocatedAndUnused() and allocate a new, empty
// and regular block. In either case, we *overly* over-allocated.
//
// Therefore, setting the last block to be at most "0.75 full" avoids both
// cases.
//
// NOTE: the average percentage of waste space of this approach can be counted
// as: "arena block size * 0.25 / write buffer size". User who specify a small
// write buffer size and/or big arena block size may suffer.
return arena_.AllocatedAndUnused() < kArenaBlockSize / 4;
}
void MemTable::UpdateFlushState() {
auto state = flush_state_.load(std::memory_order_relaxed);
if (state == FLUSH_NOT_REQUESTED && ShouldFlushNow()) {
// ignore CAS failure, because that means somebody else requested
// a flush
flush_state_.compare_exchange_strong(state, FLUSH_REQUESTED,
std::memory_order_relaxed,
std::memory_order_relaxed);
}
}
void MemTable::UpdateOldestKeyTime() {
uint64_t oldest_key_time = oldest_key_time_.load(std::memory_order_relaxed);
if (oldest_key_time == std::numeric_limits<uint64_t>::max()) {
int64_t current_time = 0;
auto s = clock_->GetCurrentTime(&current_time);
if (s.ok()) {
assert(current_time >= 0);
// If fail, the timestamp is already set.
oldest_key_time_.compare_exchange_strong(
oldest_key_time, static_cast<uint64_t>(current_time),
std::memory_order_relaxed, std::memory_order_relaxed);
}
}
}
Status MemTable::VerifyEntryChecksum(const char* entry,
size_t protection_bytes_per_key,
bool allow_data_in_errors) {
if (protection_bytes_per_key == 0) {
return Status::OK();
}
uint32_t key_length;
const char* key_ptr = GetVarint32Ptr(entry, entry + 5, &key_length);
if (key_ptr == nullptr) {
return Status::Corruption("Unable to parse internal key length");
}
if (key_length < 8) {
return Status::Corruption("Memtable entry internal key length too short.");
}
Slice user_key = Slice(key_ptr, key_length - 8);
const uint64_t tag = DecodeFixed64(key_ptr + key_length - 8);
ValueType type;
SequenceNumber seq;
UnPackSequenceAndType(tag, &seq, &type);
uint32_t value_length = 0;
const char* value_ptr = GetVarint32Ptr(
key_ptr + key_length, key_ptr + key_length + 5, &value_length);
if (value_ptr == nullptr) {
return Status::Corruption("Unable to parse internal key value");
}
Slice value = Slice(value_ptr, value_length);
const char* checksum_ptr = value_ptr + value_length;
uint64_t expected = ProtectionInfo64()
.ProtectKVO(user_key, value, type)
.ProtectS(seq)
.GetVal();
bool match = true;
switch (protection_bytes_per_key) {
case 1:
match = static_cast<uint8_t>(checksum_ptr[0]) ==
static_cast<uint8_t>(expected);
break;
case 2:
match = DecodeFixed16(checksum_ptr) == static_cast<uint16_t>(expected);
break;
case 4:
match = DecodeFixed32(checksum_ptr) == static_cast<uint32_t>(expected);
break;
case 8:
match = DecodeFixed64(checksum_ptr) == expected;
break;
default:
assert(false);
}
if (!match) {
std::string msg(
"Corrupted memtable entry, per key-value checksum verification "
"failed.");
if (allow_data_in_errors) {
msg.append("Unrecognized value type: " +
std::to_string(static_cast<int>(type)) + ". ");
msg.append("User key: " + user_key.ToString(/*hex=*/true) + ". ");
msg.append("seq: " + std::to_string(seq) + ".");
}
return Status::Corruption(msg.c_str());
}
return Status::OK();
}
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.CompareKeySeq(k1, k2);
}
int MemTable::KeyComparator::operator()(
const char* prefix_len_key, const KeyComparator::DecodedType& key) const {
// Internal keys are encoded as length-prefixed strings.
Slice a = GetLengthPrefixedSlice(prefix_len_key);
return comparator.CompareKeySeq(a, key);
}
void MemTableRep::InsertConcurrently(KeyHandle /*handle*/) {
#ifndef ROCKSDB_LITE
throw std::runtime_error("concurrent insert not supported");
#else
abort();
#endif
}
Slice MemTableRep::UserKey(const char* key) const {
Slice slice = GetLengthPrefixedSlice(key);
return Slice(slice.data(), slice.size() - 8);
}
KeyHandle MemTableRep::Allocate(const size_t len, char** buf) {
*buf = allocator_->Allocate(len);
return static_cast<KeyHandle>(*buf);
}
// 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, static_cast<uint32_t>(target.size()));
scratch->append(target.data(), target.size());
return scratch->data();
}
class MemTableIterator : public InternalIterator {
public:
MemTableIterator(const MemTable& mem, const ReadOptions& read_options,
Arena* arena, bool use_range_del_table = false)
: bloom_(nullptr),
prefix_extractor_(mem.prefix_extractor_),
comparator_(mem.comparator_),
valid_(false),
arena_mode_(arena != nullptr),
value_pinned_(
!mem.GetImmutableMemTableOptions()->inplace_update_support),
protection_bytes_per_key_(mem.moptions_.protection_bytes_per_key),
status_(Status::OK()),
logger_(mem.moptions_.info_log) {
if (use_range_del_table) {
iter_ = mem.range_del_table_->GetIterator(arena);
} else if (prefix_extractor_ != nullptr && !read_options.total_order_seek &&
!read_options.auto_prefix_mode) {
// Auto prefix mode is not implemented in memtable yet.
bloom_ = mem.bloom_filter_.get();
iter_ = mem.table_->GetDynamicPrefixIterator(arena);
} else {
iter_ = mem.table_->GetIterator(arena);
}
status_.PermitUncheckedError();
}
// No copying allowed
MemTableIterator(const MemTableIterator&) = delete;
void operator=(const MemTableIterator&) = delete;
~MemTableIterator() override {
#ifndef NDEBUG
// Assert that the MemTableIterator is never deleted while
// Pinning is Enabled.
assert(!pinned_iters_mgr_ || !pinned_iters_mgr_->PinningEnabled());
#endif
if (arena_mode_) {
iter_->~Iterator();
} else {
delete iter_;
}
}
#ifndef NDEBUG
void SetPinnedItersMgr(PinnedIteratorsManager* pinned_iters_mgr) override {
pinned_iters_mgr_ = pinned_iters_mgr;
}
PinnedIteratorsManager* pinned_iters_mgr_ = nullptr;
#endif
bool Valid() const override { return valid_ && status_.ok(); }
void Seek(const Slice& k) override {
PERF_TIMER_GUARD(seek_on_memtable_time);
PERF_COUNTER_ADD(seek_on_memtable_count, 1);
if (bloom_) {
// iterator should only use prefix bloom filter
auto ts_sz = comparator_.comparator.user_comparator()->timestamp_size();
Slice user_k_without_ts(ExtractUserKeyAndStripTimestamp(k, ts_sz));
if (prefix_extractor_->InDomain(user_k_without_ts)) {
if (!bloom_->MayContain(
prefix_extractor_->Transform(user_k_without_ts))) {
PERF_COUNTER_ADD(bloom_memtable_miss_count, 1);
valid_ = false;
return;
} else {
PERF_COUNTER_ADD(bloom_memtable_hit_count, 1);
}
}
}
iter_->Seek(k, nullptr);
valid_ = iter_->Valid();
VerifyEntryChecksum();
}
void SeekForPrev(const Slice& k) override {
PERF_TIMER_GUARD(seek_on_memtable_time);
PERF_COUNTER_ADD(seek_on_memtable_count, 1);
if (bloom_) {
auto ts_sz = comparator_.comparator.user_comparator()->timestamp_size();
Slice user_k_without_ts(ExtractUserKeyAndStripTimestamp(k, ts_sz));
if (prefix_extractor_->InDomain(user_k_without_ts)) {
if (!bloom_->MayContain(
prefix_extractor_->Transform(user_k_without_ts))) {
PERF_COUNTER_ADD(bloom_memtable_miss_count, 1);
valid_ = false;
return;
} else {
PERF_COUNTER_ADD(bloom_memtable_hit_count, 1);
}
}
}
iter_->Seek(k, nullptr);
valid_ = iter_->Valid();
VerifyEntryChecksum();
if (!Valid() && status().ok()) {
SeekToLast();
}
while (Valid() && comparator_.comparator.Compare(k, key()) < 0) {
Prev();
}
}
void SeekToFirst() override {
iter_->SeekToFirst();
valid_ = iter_->Valid();
VerifyEntryChecksum();
}
void SeekToLast() override {
iter_->SeekToLast();
valid_ = iter_->Valid();
VerifyEntryChecksum();
}
void Next() override {
PERF_COUNTER_ADD(next_on_memtable_count, 1);
assert(Valid());
iter_->Next();
TEST_SYNC_POINT_CALLBACK("MemTableIterator::Next:0", iter_);
valid_ = iter_->Valid();
VerifyEntryChecksum();
}
bool NextAndGetResult(IterateResult* result) override {
Next();
bool is_valid = Valid();
if (is_valid) {
result->key = key();
result->bound_check_result = IterBoundCheck::kUnknown;
result->value_prepared = true;
}
return is_valid;
}
void Prev() override {
PERF_COUNTER_ADD(prev_on_memtable_count, 1);
assert(Valid());
iter_->Prev();
valid_ = iter_->Valid();
VerifyEntryChecksum();
}
Slice key() const override {
assert(Valid());
return GetLengthPrefixedSlice(iter_->key());
}
Slice value() const override {
assert(Valid());
Slice key_slice = GetLengthPrefixedSlice(iter_->key());
return GetLengthPrefixedSlice(key_slice.data() + key_slice.size());
}
Status status() const override { return status_; }
bool IsKeyPinned() const override {
// memtable data is always pinned
return true;
}
bool IsValuePinned() const override {
// memtable value is always pinned, except if we allow inplace update.
return value_pinned_;
}
private:
DynamicBloom* bloom_;
const SliceTransform* const prefix_extractor_;
const MemTable::KeyComparator comparator_;
MemTableRep::Iterator* iter_;
bool valid_;
bool arena_mode_;
bool value_pinned_;
size_t protection_bytes_per_key_;
Status status_;
Logger* logger_;
void VerifyEntryChecksum() {
if (protection_bytes_per_key_ > 0 && Valid()) {
status_ = MemTable::VerifyEntryChecksum(iter_->key(),
protection_bytes_per_key_);
if (!status_.ok()) {
ROCKS_LOG_ERROR(logger_, "In MemtableIterator: %s", status_.getState());
}
}
}
};
InternalIterator* MemTable::NewIterator(const ReadOptions& read_options,
Arena* arena) {
assert(arena != nullptr);
auto mem = arena->AllocateAligned(sizeof(MemTableIterator));
return new (mem) MemTableIterator(*this, read_options, arena);
}
FragmentedRangeTombstoneIterator* MemTable::NewRangeTombstoneIterator(
const ReadOptions& read_options, SequenceNumber read_seq,
bool immutable_memtable) {
if (read_options.ignore_range_deletions ||
is_range_del_table_empty_.load(std::memory_order_relaxed)) {
return nullptr;
}
return NewRangeTombstoneIteratorInternal(read_options, read_seq,
immutable_memtable);
}
FragmentedRangeTombstoneIterator* MemTable::NewRangeTombstoneIteratorInternal(
const ReadOptions& read_options, SequenceNumber read_seq,
bool immutable_memtable) {
if (immutable_memtable) {
// Note that caller should already have verified that
// !is_range_del_table_empty_
assert(IsFragmentedRangeTombstonesConstructed());
return new FragmentedRangeTombstoneIterator(
fragmented_range_tombstone_list_.get(), comparator_.comparator,
read_seq, read_options.timestamp);
}
// takes current cache
std::shared_ptr<FragmentedRangeTombstoneListCache> cache =
std::atomic_load_explicit(cached_range_tombstone_.Access(),
std::memory_order_relaxed);
// construct fragmented tombstone list if necessary
if (!cache->initialized.load(std::memory_order_acquire)) {
cache->reader_mutex.lock();
if (!cache->tombstones) {
auto* unfragmented_iter =
new MemTableIterator(*this, read_options, nullptr /* arena */,
true /* use_range_del_table */);
cache->tombstones.reset(new FragmentedRangeTombstoneList(
std::unique_ptr<InternalIterator>(unfragmented_iter),
comparator_.comparator));
cache->initialized.store(true, std::memory_order_release);
}
cache->reader_mutex.unlock();
}
auto* fragmented_iter = new FragmentedRangeTombstoneIterator(
cache, comparator_.comparator, read_seq, read_options.timestamp);
return fragmented_iter;
}
void MemTable::ConstructFragmentedRangeTombstones() {
assert(!IsFragmentedRangeTombstonesConstructed(false));
// There should be no concurrent Construction
if (!is_range_del_table_empty_.load(std::memory_order_relaxed)) {
auto* unfragmented_iter =
new MemTableIterator(*this, ReadOptions(), nullptr /* arena */,
true /* use_range_del_table */);
fragmented_range_tombstone_list_ =
std::make_unique<FragmentedRangeTombstoneList>(
std::unique_ptr<InternalIterator>(unfragmented_iter),
comparator_.comparator);
}
}
port::RWMutex* MemTable::GetLock(const Slice& key) {
return &locks_[GetSliceRangedNPHash(key, locks_.size())];
}
MemTable::MemTableStats MemTable::ApproximateStats(const Slice& start_ikey,
const Slice& end_ikey) {
uint64_t entry_count = table_->ApproximateNumEntries(start_ikey, end_ikey);
entry_count += range_del_table_->ApproximateNumEntries(start_ikey, end_ikey);
if (entry_count == 0) {
return {0, 0};
}
uint64_t n = num_entries_.load(std::memory_order_relaxed);
if (n == 0) {
return {0, 0};
}
if (entry_count > n) {
// (range_del_)table_->ApproximateNumEntries() is just an estimate so it can
// be larger than actual entries we have. Cap it to entries we have to limit
// the inaccuracy.
entry_count = n;
}
uint64_t data_size = data_size_.load(std::memory_order_relaxed);
return {entry_count * (data_size / n), entry_count};
}
Status MemTable::VerifyEncodedEntry(Slice encoded,
const ProtectionInfoKVOS64& kv_prot_info) {
uint32_t ikey_len = 0;
if (!GetVarint32(&encoded, &ikey_len)) {
return Status::Corruption("Unable to parse internal key length");
}
size_t ts_sz = GetInternalKeyComparator().user_comparator()->timestamp_size();
if (ikey_len < 8 + ts_sz) {
return Status::Corruption("Internal key length too short");
}
if (ikey_len > encoded.size()) {
return Status::Corruption("Internal key length too long");
}
uint32_t value_len = 0;
const size_t user_key_len = ikey_len - 8;
Slice key(encoded.data(), user_key_len);
encoded.remove_prefix(user_key_len);
uint64_t packed = DecodeFixed64(encoded.data());
ValueType value_type = kMaxValue;
SequenceNumber sequence_number = kMaxSequenceNumber;
UnPackSequenceAndType(packed, &sequence_number, &value_type);
encoded.remove_prefix(8);
if (!GetVarint32(&encoded, &value_len)) {
return Status::Corruption("Unable to parse value length");
}
if (value_len < encoded.size()) {
return Status::Corruption("Value length too short");
}
if (value_len > encoded.size()) {
return Status::Corruption("Value length too long");
}
Slice value(encoded.data(), value_len);
return kv_prot_info.StripS(sequence_number)
.StripKVO(key, value, value_type)
.GetStatus();
}
void MemTable::UpdateEntryChecksum(const ProtectionInfoKVOS64* kv_prot_info,
const Slice& key, const Slice& value,
ValueType type, SequenceNumber s,
char* checksum_ptr) {
if (moptions_.protection_bytes_per_key == 0) {
return;
}
uint64_t checksum = 0;
if (kv_prot_info == nullptr) {
checksum =
ProtectionInfo64().ProtectKVO(key, value, type).ProtectS(s).GetVal();
} else {
checksum = kv_prot_info->GetVal();
}
switch (moptions_.protection_bytes_per_key) {
case 1:
checksum_ptr[0] = static_cast<uint8_t>(checksum);
break;
case 2:
EncodeFixed16(checksum_ptr, static_cast<uint16_t>(checksum));
break;
case 4:
EncodeFixed32(checksum_ptr, static_cast<uint32_t>(checksum));
break;
case 8:
EncodeFixed64(checksum_ptr, checksum);
break;
default:
assert(false);
}
}
Status MemTable::Add(SequenceNumber s, ValueType type,
const Slice& key, /* user key */
const Slice& value,
const ProtectionInfoKVOS64* kv_prot_info,
bool allow_concurrent,
MemTablePostProcessInfo* post_process_info, void** hint) {
// 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()]
// checksum : char[moptions_.protection_bytes_per_key]
uint32_t key_size = static_cast<uint32_t>(key.size());
uint32_t val_size = static_cast<uint32_t>(value.size());
uint32_t internal_key_size = key_size + 8;
const uint32_t encoded_len = VarintLength(internal_key_size) +
internal_key_size + VarintLength(val_size) +
val_size + moptions_.protection_bytes_per_key;
char* buf = nullptr;
std::unique_ptr<MemTableRep>& table =
type == kTypeRangeDeletion ? range_del_table_ : table_;
KeyHandle handle = table->Allocate(encoded_len, &buf);
char* p = EncodeVarint32(buf, internal_key_size);
memcpy(p, key.data(), key_size);
Slice key_slice(p, key_size);
p += key_size;
uint64_t packed = PackSequenceAndType(s, type);
EncodeFixed64(p, packed);
p += 8;
p = EncodeVarint32(p, val_size);
memcpy(p, value.data(), val_size);
assert((unsigned)(p + val_size - buf + moptions_.protection_bytes_per_key) ==
(unsigned)encoded_len);
UpdateEntryChecksum(kv_prot_info, key, value, type, s,
buf + encoded_len - moptions_.protection_bytes_per_key);
Slice encoded(buf, encoded_len - moptions_.protection_bytes_per_key);
if (kv_prot_info != nullptr) {
TEST_SYNC_POINT_CALLBACK("MemTable::Add:Encoded", &encoded);
Status status = VerifyEncodedEntry(encoded, *kv_prot_info);
if (!status.ok()) {
return status;
}
}
size_t ts_sz = GetInternalKeyComparator().user_comparator()->timestamp_size();
Slice key_without_ts = StripTimestampFromUserKey(key, ts_sz);
if (!allow_concurrent) {
// Extract prefix for insert with hint.
if (insert_with_hint_prefix_extractor_ != nullptr &&
insert_with_hint_prefix_extractor_->InDomain(key_slice)) {
Slice prefix = insert_with_hint_prefix_extractor_->Transform(key_slice);
bool res = table->InsertKeyWithHint(handle, &insert_hints_[prefix]);
if (UNLIKELY(!res)) {
return Status::TryAgain("key+seq exists");
}
} else {
bool res = table->InsertKey(handle);
if (UNLIKELY(!res)) {
return Status::TryAgain("key+seq exists");
}
}
// this is a bit ugly, but is the way to avoid locked instructions
// when incrementing an atomic
num_entries_.store(num_entries_.load(std::memory_order_relaxed) + 1,
std::memory_order_relaxed);
data_size_.store(data_size_.load(std::memory_order_relaxed) + encoded_len,
std::memory_order_relaxed);
if (type == kTypeDeletion || type == kTypeSingleDeletion ||
type == kTypeDeletionWithTimestamp) {
num_deletes_.store(num_deletes_.load(std::memory_order_relaxed) + 1,
std::memory_order_relaxed);
}
if (bloom_filter_ && prefix_extractor_ &&
prefix_extractor_->InDomain(key_without_ts)) {
bloom_filter_->Add(prefix_extractor_->Transform(key_without_ts));
}
if (bloom_filter_ && moptions_.memtable_whole_key_filtering) {
bloom_filter_->Add(key_without_ts);
}
// The first sequence number inserted into the memtable
assert(first_seqno_ == 0 || s >= first_seqno_);
if (first_seqno_ == 0) {
first_seqno_.store(s, std::memory_order_relaxed);
if (earliest_seqno_ == kMaxSequenceNumber) {
earliest_seqno_.store(GetFirstSequenceNumber(),
std::memory_order_relaxed);
}
assert(first_seqno_.load() >= earliest_seqno_.load());
}
assert(post_process_info == nullptr);
UpdateFlushState();
} else {
bool res = (hint == nullptr)
? table->InsertKeyConcurrently(handle)
: table->InsertKeyWithHintConcurrently(handle, hint);
if (UNLIKELY(!res)) {
return Status::TryAgain("key+seq exists");
}
assert(post_process_info != nullptr);
post_process_info->num_entries++;
post_process_info->data_size += encoded_len;
if (type == kTypeDeletion) {
post_process_info->num_deletes++;
}
if (bloom_filter_ && prefix_extractor_ &&
prefix_extractor_->InDomain(key_without_ts)) {
bloom_filter_->AddConcurrently(
prefix_extractor_->Transform(key_without_ts));
}
if (bloom_filter_ && moptions_.memtable_whole_key_filtering) {
bloom_filter_->AddConcurrently(key_without_ts);
}
// atomically update first_seqno_ and earliest_seqno_.
uint64_t cur_seq_num = first_seqno_.load(std::memory_order_relaxed);
while ((cur_seq_num == 0 || s < cur_seq_num) &&
!first_seqno_.compare_exchange_weak(cur_seq_num, s)) {
}
uint64_t cur_earliest_seqno =
earliest_seqno_.load(std::memory_order_relaxed);
while (
(cur_earliest_seqno == kMaxSequenceNumber || s < cur_earliest_seqno) &&
!first_seqno_.compare_exchange_weak(cur_earliest_seqno, s)) {
}
}
if (type == kTypeRangeDeletion) {
auto new_cache = std::make_shared<FragmentedRangeTombstoneListCache>();
size_t size = cached_range_tombstone_.Size();
if (allow_concurrent) {
range_del_mutex_.lock();
}
for (size_t i = 0; i < size; ++i) {
std::shared_ptr<FragmentedRangeTombstoneListCache>* local_cache_ref_ptr =
cached_range_tombstone_.AccessAtCore(i);
auto new_local_cache_ref = std::make_shared<
const std::shared_ptr<FragmentedRangeTombstoneListCache>>(new_cache);
// It is okay for some reader to load old cache during invalidation as
// the new sequence number is not published yet.
// Each core will have a shared_ptr to a shared_ptr to the cached
// fragmented range tombstones, so that ref count is maintianed locally
// per-core using the per-core shared_ptr.
std::atomic_store_explicit(
local_cache_ref_ptr,
std::shared_ptr<FragmentedRangeTombstoneListCache>(
new_local_cache_ref, new_cache.get()),
std::memory_order_relaxed);
}
if (allow_concurrent) {
range_del_mutex_.unlock();
}
is_range_del_table_empty_.store(false, std::memory_order_relaxed);
}
UpdateOldestKeyTime();
TEST_SYNC_POINT_CALLBACK("MemTable::Add:BeforeReturn:Encoded", &encoded);
return Status::OK();
}
// 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;
PinnableWideColumns* columns;
SequenceNumber seq;
std::string* timestamp;
const MergeOperator* merge_operator;
// the merge operations encountered;
MergeContext* merge_context;
SequenceNumber max_covering_tombstone_seq;
MemTable* mem;
Logger* logger;
Statistics* statistics;
bool inplace_update_support;
bool do_merge;
SystemClock* clock;
ReadCallback* callback_;
bool* is_blob_index;
bool allow_data_in_errors;
size_t protection_bytes_per_key;
bool CheckCallback(SequenceNumber _seq) {
if (callback_) {
return callback_->IsVisible(_seq);
}
return true;
}
};
} // anonymous namespace
static bool SaveValue(void* arg, const char* entry) {
TEST_SYNC_POINT_CALLBACK("Memtable::SaveValue:Begin:entry", &entry);
Saver* s = reinterpret_cast<Saver*>(arg);
assert(s != nullptr);
assert(!s->value || !s->columns);
if (s->protection_bytes_per_key > 0) {
*(s->status) = MemTable::VerifyEntryChecksum(
entry, s->protection_bytes_per_key, s->allow_data_in_errors);
if (!s->status->ok()) {
ROCKS_LOG_ERROR(s->logger, "In SaveValue: %s", s->status->getState());
// Memtable entry corrupted
return false;
}
}
MergeContext* merge_context = s->merge_context;
SequenceNumber max_covering_tombstone_seq = s->max_covering_tombstone_seq;
const MergeOperator* merge_operator = s->merge_operator;
assert(merge_context != nullptr);
// Refer to comments under MemTable::Add() for entry format.
// Check that it belongs to same user key.
uint32_t key_length = 0;
const char* key_ptr = GetVarint32Ptr(entry, entry + 5, &key_length);
assert(key_length >= 8);
Slice user_key_slice = Slice(key_ptr, key_length - 8);
const Comparator* user_comparator =
s->mem->GetInternalKeyComparator().user_comparator();
size_t ts_sz = user_comparator->timestamp_size();
if (ts_sz && s->timestamp && max_covering_tombstone_seq > 0) {
// timestamp should already be set to range tombstone timestamp
assert(s->timestamp->size() == ts_sz);
}
if (user_comparator->EqualWithoutTimestamp(user_key_slice,
s->key->user_key())) {
// Correct user key
const uint64_t tag = DecodeFixed64(key_ptr + key_length - 8);
ValueType type;
SequenceNumber seq;
UnPackSequenceAndType(tag, &seq, &type);
// If the value is not in the snapshot, skip it
if (!s->CheckCallback(seq)) {
return true; // to continue to the next seq
}
if (s->seq == kMaxSequenceNumber) {
s->seq = seq;
if (s->seq > max_covering_tombstone_seq) {
if (ts_sz && s->timestamp != nullptr) {
// `timestamp` was set to range tombstone's timestamp before
// `SaveValue` is ever called. This key has a higher sequence number
// than range tombstone, and is the key with the highest seqno across
// all keys with this user_key, so we update timestamp here.
Slice ts = ExtractTimestampFromUserKey(user_key_slice, ts_sz);
s->timestamp->assign(ts.data(), ts_sz);
}
} else {
s->seq = max_covering_tombstone_seq;
}
}
if (ts_sz > 0 && s->timestamp != nullptr) {
if (!s->timestamp->empty()) {
assert(ts_sz == s->timestamp->size());
}
// TODO optimize for smaller size ts
const std::string kMaxTs(ts_sz, '\xff');
if (s->timestamp->empty() ||
user_comparator->CompareTimestamp(*(s->timestamp), kMaxTs) == 0) {
Slice ts = ExtractTimestampFromUserKey(user_key_slice, ts_sz);
s->timestamp->assign(ts.data(), ts_sz);
}
}
if ((type == kTypeValue || type == kTypeMerge || type == kTypeBlobIndex ||
type == kTypeWideColumnEntity || type == kTypeDeletion ||
type == kTypeSingleDeletion || type == kTypeDeletionWithTimestamp) &&
max_covering_tombstone_seq > seq) {
type = kTypeRangeDeletion;
}
switch (type) {
case kTypeBlobIndex: {
if (!s->do_merge) {
*(s->status) = Status::NotSupported(
"GetMergeOperands not supported by stacked BlobDB");
*(s->found_final_value) = true;
return false;
}
if (*(s->merge_in_progress)) {
*(s->status) = Status::NotSupported(
"Merge operator not supported by stacked BlobDB");
*(s->found_final_value) = true;
return false;
}
if (s->is_blob_index == nullptr) {
ROCKS_LOG_ERROR(s->logger, "Encountered unexpected blob index.");
*(s->status) = Status::NotSupported(
"Encountered unexpected blob index. Please open DB with "
"ROCKSDB_NAMESPACE::blob_db::BlobDB.");
*(s->found_final_value) = true;
return false;
}
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->value) {
s->value->assign(v.data(), v.size());
} else if (s->columns) {
s->columns->SetPlainValue(v);
}
if (s->inplace_update_support) {
s->mem->GetLock(s->key->user_key())->ReadUnlock();
}
*(s->found_final_value) = true;
*(s->is_blob_index) = true;
return false;
}
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->do_merge) {
// Preserve the value with the goal of returning it as part of
// raw merge operands to the user
// TODO(yanqin) update MergeContext so that timestamps information
// can also be retained.
merge_context->PushOperand(
v, s->inplace_update_support == false /* operand_pinned */);
} else if (*(s->merge_in_progress)) {
assert(s->do_merge);
if (s->value || s->columns) {
std::string result;
*(s->status) = MergeHelper::TimedFullMerge(
merge_operator, s->key->user_key(), &v,
merge_context->GetOperands(), &result, s->logger, s->statistics,
s->clock, /* result_operand */ nullptr,
/* update_num_ops_stats */ true);
if (s->status->ok()) {
if (s->value) {
*(s->value) = std::move(result);
} else {
assert(s->columns);
s->columns->SetPlainValue(result);
}
}
}
} else if (s->value) {
s->value->assign(v.data(), v.size());
} else if (s->columns) {
s->columns->SetPlainValue(v);
}
if (s->inplace_update_support) {
s->mem->GetLock(s->key->user_key())->ReadUnlock();
}
*(s->found_final_value) = true;
if (s->is_blob_index != nullptr) {
*(s->is_blob_index) = false;
}
return false;
}
case kTypeWideColumnEntity: {
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->do_merge) {
// Preserve the value with the goal of returning it as part of
// raw merge operands to the user
Slice value_of_default;
*(s->status) = WideColumnSerialization::GetValueOfDefaultColumn(
v, value_of_default);
if (s->status->ok()) {
merge_context->PushOperand(
value_of_default,
s->inplace_update_support == false /* operand_pinned */);
}
} else if (*(s->merge_in_progress)) {
assert(s->do_merge);
if (s->value) {
Slice value_of_default;
*(s->status) = WideColumnSerialization::GetValueOfDefaultColumn(
v, value_of_default);
if (s->status->ok()) {
*(s->status) = MergeHelper::TimedFullMerge(
merge_operator, s->key->user_key(), &value_of_default,
merge_context->GetOperands(), s->value, s->logger,
s->statistics, s->clock, /* result_operand */ nullptr,
/* update_num_ops_stats */ true);
}
} else if (s->columns) {
std::string result;
*(s->status) = MergeHelper::TimedFullMergeWithEntity(
merge_operator, s->key->user_key(), v,
merge_context->GetOperands(), &result, s->logger, s->statistics,
s->clock, /* update_num_ops_stats */ true);
if (s->status->ok()) {
*(s->status) = s->columns->SetWideColumnValue(result);
}
}
} else if (s->value) {
Slice value_of_default;
*(s->status) = WideColumnSerialization::GetValueOfDefaultColumn(
v, value_of_default);
if (s->status->ok()) {
s->value->assign(value_of_default.data(), value_of_default.size());
}
} else if (s->columns) {
*(s->status) = s->columns->SetWideColumnValue(v);
}
if (s->inplace_update_support) {
s->mem->GetLock(s->key->user_key())->ReadUnlock();
}
*(s->found_final_value) = true;
if (s->is_blob_index != nullptr) {
*(s->is_blob_index) = false;
}
return false;
}
case kTypeDeletion:
case kTypeDeletionWithTimestamp:
case kTypeSingleDeletion:
case kTypeRangeDeletion: {
if (*(s->merge_in_progress)) {
if (s->value || s->columns) {
std::string result;
*(s->status) = MergeHelper::TimedFullMerge(
merge_operator, s->key->user_key(), nullptr,
merge_context->GetOperands(), &result, s->logger, s->statistics,
s->clock, /* result_operand */ nullptr,
/* update_num_ops_stats */ true);
if (s->status->ok()) {
if (s->value) {
*(s->value) = std::move(result);
} else {
assert(s->columns);
s->columns->SetPlainValue(result);
}
}
}
} else {
*(s->status) = Status::NotFound();
}
*(s->found_final_value) = true;
return false;
}
case kTypeMerge: {
if (!merge_operator) {
*(s->status) = Status::InvalidArgument(
"merge_operator is not properly initialized.");
// Normally we continue the loop (return true) when we see a merge
// operand. But in case of an error, we should stop the loop
// immediately and pretend we have found the value to stop further
// seek. Otherwise, the later call will override this error status.
*(s->found_final_value) = true;
return false;
}
Slice v = GetLengthPrefixedSlice(key_ptr + key_length);
*(s->merge_in_progress) = true;
merge_context->PushOperand(
v, s->inplace_update_support == false /* operand_pinned */);
if (s->do_merge && merge_operator->ShouldMerge(
merge_context->GetOperandsDirectionBackward())) {
if (s->value || s->columns) {
std::string result;
*(s->status) = MergeHelper::TimedFullMerge(
merge_operator, s->key->user_key(), nullptr,
merge_context->GetOperands(), &result, s->logger, s->statistics,
s->clock, /* result_operand */ nullptr,
/* update_num_ops_stats */ true);
if (s->status->ok()) {
if (s->value) {
*(s->value) = std::move(result);
} else {
assert(s->columns);
s->columns->SetPlainValue(result);
}
}
}
*(s->found_final_value) = true;
return false;
}
return true;
}
default: {
std::string msg("Corrupted value not expected.");
if (s->allow_data_in_errors) {
msg.append("Unrecognized value type: " +
std::to_string(static_cast<int>(type)) + ". ");
msg.append("User key: " + user_key_slice.ToString(/*hex=*/true) +
". ");
msg.append("seq: " + std::to_string(seq) + ".");
}
*(s->status) = Status::Corruption(msg.c_str());
return false;
}
}
}
// s->state could be Corrupt, merge or notfound
return false;
}
bool MemTable::Get(const LookupKey& key, std::string* value,
PinnableWideColumns* columns, std::string* timestamp,
Status* s, MergeContext* merge_context,
SequenceNumber* max_covering_tombstone_seq,
SequenceNumber* seq, const ReadOptions& read_opts,
bool immutable_memtable, ReadCallback* callback,
bool* is_blob_index, bool do_merge) {
// The sequence number is updated synchronously in version_set.h
if (IsEmpty()) {
// Avoiding recording stats for speed.
return false;
}
PERF_TIMER_GUARD(get_from_memtable_time);
std::unique_ptr<FragmentedRangeTombstoneIterator> range_del_iter(
NewRangeTombstoneIterator(read_opts,
GetInternalKeySeqno(key.internal_key()),
immutable_memtable));
if (range_del_iter != nullptr) {
SequenceNumber covering_seq =
range_del_iter->MaxCoveringTombstoneSeqnum(key.user_key());
if (covering_seq > *max_covering_tombstone_seq) {
*max_covering_tombstone_seq = covering_seq;
if (timestamp) {
// Will be overwritten in SaveValue() if there is a point key with
// a higher seqno.
timestamp->assign(range_del_iter->timestamp().data(),
range_del_iter->timestamp().size());
}
}
}
bool found_final_value = false;
bool merge_in_progress = s->IsMergeInProgress();
bool may_contain = true;
size_t ts_sz = GetInternalKeyComparator().user_comparator()->timestamp_size();
Slice user_key_without_ts = StripTimestampFromUserKey(key.user_key(), ts_sz);
bool bloom_checked = false;
if (bloom_filter_) {
// when both memtable_whole_key_filtering and prefix_extractor_ are set,
// only do whole key filtering for Get() to save CPU
if (moptions_.memtable_whole_key_filtering) {
may_contain = bloom_filter_->MayContain(user_key_without_ts);
bloom_checked = true;
} else {
assert(prefix_extractor_);
if (prefix_extractor_->InDomain(user_key_without_ts)) {
may_contain = bloom_filter_->MayContain(
prefix_extractor_->Transform(user_key_without_ts));
bloom_checked = true;
}
}
}
if (bloom_filter_ && !may_contain) {
// iter is null if prefix bloom says the key does not exist
PERF_COUNTER_ADD(bloom_memtable_miss_count, 1);
*seq = kMaxSequenceNumber;
} else {
if (bloom_checked) {
PERF_COUNTER_ADD(bloom_memtable_hit_count, 1);
}
GetFromTable(key, *max_covering_tombstone_seq, do_merge, callback,
is_blob_index, value, columns, timestamp, s, merge_context,
seq, &found_final_value, &merge_in_progress);
}
// No change to value, since we have not yet found a Put/Delete
// Propagate corruption error
if (!found_final_value && merge_in_progress && !s->IsCorruption()) {
*s = Status::MergeInProgress();
}
PERF_COUNTER_ADD(get_from_memtable_count, 1);
return found_final_value;
}
void MemTable::GetFromTable(const LookupKey& key,
SequenceNumber max_covering_tombstone_seq,
bool do_merge, ReadCallback* callback,
bool* is_blob_index, std::string* value,
PinnableWideColumns* columns,
std::string* timestamp, Status* s,
MergeContext* merge_context, SequenceNumber* seq,
bool* found_final_value, bool* merge_in_progress) {
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.columns = columns;
saver.timestamp = timestamp;
saver.seq = kMaxSequenceNumber;
saver.mem = this;
saver.merge_context = merge_context;
saver.max_covering_tombstone_seq = max_covering_tombstone_seq;
saver.merge_operator = moptions_.merge_operator;
saver.logger = moptions_.info_log;
saver.inplace_update_support = moptions_.inplace_update_support;
saver.statistics = moptions_.statistics;
saver.clock = clock_;
saver.callback_ = callback;
saver.is_blob_index = is_blob_index;
saver.do_merge = do_merge;
saver.allow_data_in_errors = moptions_.allow_data_in_errors;
saver.protection_bytes_per_key = moptions_.protection_bytes_per_key;
table_->Get(key, &saver, SaveValue);
*seq = saver.seq;
}
void MemTable::MultiGet(const ReadOptions& read_options, MultiGetRange* range,
ReadCallback* callback, bool immutable_memtable) {
// The sequence number is updated synchronously in version_set.h
if (IsEmpty()) {
// Avoiding recording stats for speed.
return;
}
PERF_TIMER_GUARD(get_from_memtable_time);
// For now, memtable Bloom filter is effectively disabled if there are any
// range tombstones. This is the simplest way to ensure range tombstones are
// handled. TODO: allow Bloom checks where max_covering_tombstone_seq==0
bool no_range_del = read_options.ignore_range_deletions ||
is_range_del_table_empty_.load(std::memory_order_relaxed);
MultiGetRange temp_range(*range, range->begin(), range->end());
if (bloom_filter_ && no_range_del) {
bool whole_key =
!prefix_extractor_ || moptions_.memtable_whole_key_filtering;
std::array<Slice, MultiGetContext::MAX_BATCH_SIZE> bloom_keys;
std::array<bool, MultiGetContext::MAX_BATCH_SIZE> may_match;
std::array<size_t, MultiGetContext::MAX_BATCH_SIZE> range_indexes;
int num_keys = 0;
for (auto iter = temp_range.begin(); iter != temp_range.end(); ++iter) {
if (whole_key) {
bloom_keys[num_keys] = iter->ukey_without_ts;
range_indexes[num_keys++] = iter.index();
} else if (prefix_extractor_->InDomain(iter->ukey_without_ts)) {
bloom_keys[num_keys] =
prefix_extractor_->Transform(iter->ukey_without_ts);
range_indexes[num_keys++] = iter.index();
}
}
bloom_filter_->MayContain(num_keys, &bloom_keys[0], &may_match[0]);
for (int i = 0; i < num_keys; ++i) {
if (!may_match[i]) {
temp_range.SkipIndex(range_indexes[i]);
PERF_COUNTER_ADD(bloom_memtable_miss_count, 1);
} else {
PERF_COUNTER_ADD(bloom_memtable_hit_count, 1);
}
}
}
for (auto iter = temp_range.begin(); iter != temp_range.end(); ++iter) {
bool found_final_value{false};
bool merge_in_progress = iter->s->IsMergeInProgress();
if (!no_range_del) {
std::unique_ptr<FragmentedRangeTombstoneIterator> range_del_iter(
NewRangeTombstoneIteratorInternal(
read_options, GetInternalKeySeqno(iter->lkey->internal_key()),
immutable_memtable));
SequenceNumber covering_seq =
range_del_iter->MaxCoveringTombstoneSeqnum(iter->lkey->user_key());
if (covering_seq > iter->max_covering_tombstone_seq) {
iter->max_covering_tombstone_seq = covering_seq;
if (iter->timestamp) {
// Will be overwritten in SaveValue() if there is a point key with
// a higher seqno.
iter->timestamp->assign(range_del_iter->timestamp().data(),
range_del_iter->timestamp().size());
}
}
}
SequenceNumber dummy_seq;
GetFromTable(*(iter->lkey), iter->max_covering_tombstone_seq, true,
callback, &iter->is_blob_index, iter->value->GetSelf(),
/*columns=*/nullptr, iter->timestamp, iter->s,
&(iter->merge_context), &dummy_seq, &found_final_value,
&merge_in_progress);
if (!found_final_value && merge_in_progress) {
*(iter->s) = Status::MergeInProgress();
}
if (found_final_value) {
iter->value->PinSelf();
range->AddValueSize(iter->value->size());
range->MarkKeyDone(iter);
RecordTick(moptions_.statistics, MEMTABLE_HIT);
if (range->GetValueSize() > read_options.value_size_soft_limit) {
// Set all remaining keys in range to Abort
for (auto range_iter = range->begin(); range_iter != range->end();
++range_iter) {
range->MarkKeyDone(range_iter);
*(range_iter->s) = Status::Aborted();
}
break;
}
}
}
PERF_COUNTER_ADD(get_from_memtable_count, 1);
}
Status MemTable::Update(SequenceNumber seq, ValueType value_type,
const Slice& key, const Slice& value,
const ProtectionInfoKVOS64* kv_prot_info) {
LookupKey lkey(key, seq);
Slice mem_key = lkey.memtable_key();
std::unique_ptr<MemTableRep::Iterator> iter(
table_->GetDynamicPrefixIterator());
iter->Seek(lkey.internal_key(), mem_key.data());
if (iter->Valid()) {
// Refer to comments under MemTable::Add() for entry format.
// 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()->Equal(
Slice(key_ptr, key_length - 8), lkey.user_key())) {
// Correct user key
const uint64_t tag = DecodeFixed64(key_ptr + key_length - 8);
ValueType type;
SequenceNumber existing_seq;
UnPackSequenceAndType(tag, &existing_seq, &type);
assert(existing_seq != seq);
if (type == value_type) {
Slice prev_value = GetLengthPrefixedSlice(key_ptr + key_length);
uint32_t prev_size = static_cast<uint32_t>(prev_value.size());
uint32_t new_size = static_cast<uint32_t>(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()));
RecordTick(moptions_.statistics, NUMBER_KEYS_UPDATED);
if (kv_prot_info != nullptr) {
ProtectionInfoKVOS64 updated_kv_prot_info(*kv_prot_info);
// `seq` is swallowed and `existing_seq` prevails.
updated_kv_prot_info.UpdateS(seq, existing_seq);
UpdateEntryChecksum(&updated_kv_prot_info, key, value, type,
existing_seq, p + value.size());
Slice encoded(entry, p + value.size() - entry);
return VerifyEncodedEntry(encoded, updated_kv_prot_info);
} else {
UpdateEntryChecksum(nullptr, key, value, type, existing_seq,
p + value.size());
}
return Status::OK();
}
}
}
}
// The latest value is not value_type or key doesn't exist
return Add(seq, value_type, key, value, kv_prot_info);
}
Status MemTable::UpdateCallback(SequenceNumber seq, const Slice& key,
const Slice& delta,
const ProtectionInfoKVOS64* kv_prot_info) {
LookupKey lkey(key, seq);
Slice memkey = lkey.memtable_key();
std::unique_ptr<MemTableRep::Iterator> iter(
table_->GetDynamicPrefixIterator());
iter->Seek(lkey.internal_key(), memkey.data());
if (iter->Valid()) {
// Refer to comments under MemTable::Add() for entry format.
// 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()->Equal(
Slice(key_ptr, key_length - 8), lkey.user_key())) {
// Correct user key
const uint64_t tag = DecodeFixed64(key_ptr + key_length - 8);
ValueType type;
uint64_t existing_seq;
UnPackSequenceAndType(tag, &existing_seq, &type);
if (type == kTypeValue) {
Slice prev_value = GetLengthPrefixedSlice(key_ptr + key_length);
uint32_t prev_size = static_cast<uint32_t>(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 = moptions_.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);
prev_buffer = p;
}
}
RecordTick(moptions_.statistics, NUMBER_KEYS_UPDATED);
UpdateFlushState();
Slice new_value(prev_buffer, new_prev_size);
if (kv_prot_info != nullptr) {
ProtectionInfoKVOS64 updated_kv_prot_info(*kv_prot_info);
// `seq` is swallowed and `existing_seq` prevails.
updated_kv_prot_info.UpdateS(seq, existing_seq);
updated_kv_prot_info.UpdateV(delta, new_value);
Slice encoded(entry, prev_buffer + new_prev_size - entry);
UpdateEntryChecksum(&updated_kv_prot_info, key, new_value, type,
existing_seq, prev_buffer + new_prev_size);
return VerifyEncodedEntry(encoded, updated_kv_prot_info);
} else {
UpdateEntryChecksum(nullptr, key, new_value, type, existing_seq,
prev_buffer + new_prev_size);
}
return Status::OK();
} else if (status == UpdateStatus::UPDATED) {
Status s;
if (kv_prot_info != nullptr) {
ProtectionInfoKVOS64 updated_kv_prot_info(*kv_prot_info);
updated_kv_prot_info.UpdateV(delta, str_value);
s = Add(seq, kTypeValue, key, Slice(str_value),
&updated_kv_prot_info);
} else {
s = Add(seq, kTypeValue, key, Slice(str_value),
nullptr /* kv_prot_info */);
}
RecordTick(moptions_.statistics, NUMBER_KEYS_WRITTEN);
UpdateFlushState();
return s;
} else if (status == UpdateStatus::UPDATE_FAILED) {
// `UPDATE_FAILED` is named incorrectly. It indicates no update
// happened. It does not indicate a failure happened.
UpdateFlushState();
return Status::OK();
}
}
}
}
// The latest value is not `kTypeValue` or key doesn't exist
return Status::NotFound();
}
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_->GetDynamicPrefixIterator());
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()->Equal(
Slice(iter_key_ptr, key_length - 8), key.user_key())) {
break;
}
const uint64_t tag = DecodeFixed64(iter_key_ptr + key_length - 8);
ValueType type;
uint64_t unused;
UnPackSequenceAndType(tag, &unused, &type);
if (type != 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 = GetDynamicPrefixIterator();
for (iter->Seek(k.internal_key(), k.memtable_key().data());
iter->Valid() && callback_func(callback_args, iter->key());
iter->Next()) {
}
}
void MemTable::RefLogContainingPrepSection(uint64_t log) {
assert(log > 0);
auto cur = min_prep_log_referenced_.load();
while ((log < cur || cur == 0) &&
!min_prep_log_referenced_.compare_exchange_strong(cur, log)) {
cur = min_prep_log_referenced_.load();
}
}
uint64_t MemTable::GetMinLogContainingPrepSection() {
return min_prep_log_referenced_.load();
}
} // namespace ROCKSDB_NAMESPACE
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