Avoid user key copying for Get/Put/Write with user-timestamp (#5502)
Summary:
In previous https://github.com/facebook/rocksdb/issues/5079, we added user-specified timestamp to `DB::Get()` and `DB::Put()`. Limitation is that these two functions may cause extra memory allocation and key copy. The reason is that `WriteBatch` does not allocate extra memory for timestamps because it is not aware of timestamp size, and we did not provide an API to assign/update timestamp of each key within a `WriteBatch`.
We address these issues in this PR by doing the following.
1. Add a `timestamp_size_` to `WriteBatch` so that `WriteBatch` can take timestamps into account when calling `WriteBatch::Put`, `WriteBatch::Delete`, etc.
2. Add APIs `WriteBatch::AssignTimestamp` and `WriteBatch::AssignTimestamps` so that application can assign/update timestamps for each key in a `WriteBatch`.
3. Avoid key copy in `GetImpl` by adding new constructor to `LookupKey`.
Test plan (on devserver):
```
$make clean && COMPILE_WITH_ASAN=1 make -j32 all
$./db_basic_test --gtest_filter=Timestamp/DBBasicTestWithTimestampWithParam.PutAndGet/*
$make check
```
If the API extension looks good, I will add more unit tests.
Some simple benchmark using db_bench.
```
$rm -rf /dev/shm/dbbench/* && TEST_TMPDIR=/dev/shm ./db_bench -benchmarks=fillseq,readrandom -num=1000000
$rm -rf /dev/shm/dbbench/* && TEST_TMPDIR=/dev/shm ./db_bench -benchmarks=fillrandom -num=1000000 -disable_wal=true
```
Master is at a78503bd6c.
```
| | readrandom | fillrandom |
| master | 15.53 MB/s | 25.97 MB/s |
| PR5502 | 16.70 MB/s | 25.80 MB/s |
```
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5502
Differential Revision: D16340894
Pulled By: riversand963
fbshipit-source-id: 51132cf792be07d1efc3ac33f5768c4ee2608bb8
This commit is contained in:
Yanqin Jin
Facebook Github Bot
parent
0d16fad51b
commit
ae152ee666
1
.gitignore
vendored
1
.gitignore
vendored
@ -49,6 +49,7 @@ rocksdb_undump
|
||||
db_test2
|
||||
trace_analyzer
|
||||
trace_analyzer_test
|
||||
block_cache_trace_analyzer
|
||||
.DS_Store
|
||||
|
||||
java/out
|
||||
|
||||
@ -1441,17 +1441,8 @@ ColumnFamilyHandle* DBImpl::PersistentStatsColumnFamily() const {
|
||||
Status DBImpl::Get(const ReadOptions& read_options,
|
||||
ColumnFamilyHandle* column_family, const Slice& key,
|
||||
PinnableSlice* value) {
|
||||
if (nullptr == read_options.timestamp) {
|
||||
return GetImpl(read_options, column_family, key, value);
|
||||
}
|
||||
Slice akey;
|
||||
std::string buf;
|
||||
Status s = AppendTimestamp(key, *(read_options.timestamp), &akey, &buf);
|
||||
if (s.ok()) {
|
||||
s = GetImpl(read_options, column_family, akey, value);
|
||||
}
|
||||
return s;
|
||||
}
|
||||
|
||||
Status DBImpl::GetImpl(const ReadOptions& read_options,
|
||||
ColumnFamilyHandle* column_family, const Slice& key,
|
||||
@ -1528,7 +1519,7 @@ Status DBImpl::GetImpl(const ReadOptions& read_options,
|
||||
// First look in the memtable, then in the immutable memtable (if any).
|
||||
// s is both in/out. When in, s could either be OK or MergeInProgress.
|
||||
// merge_operands will contain the sequence of merges in the latter case.
|
||||
LookupKey lkey(key, snapshot);
|
||||
LookupKey lkey(key, snapshot, read_options.timestamp);
|
||||
PERF_TIMER_STOP(get_snapshot_time);
|
||||
|
||||
bool skip_memtable = (read_options.read_tier == kPersistedTier &&
|
||||
|
||||
@ -1734,14 +1734,16 @@ Status DB::Put(const WriteOptions& opt, ColumnFamilyHandle* column_family,
|
||||
}
|
||||
return Write(opt, &batch);
|
||||
}
|
||||
Slice akey;
|
||||
std::string buf;
|
||||
Status s = AppendTimestamp(key, *(opt.timestamp), &akey, &buf);
|
||||
const Slice* ts = opt.timestamp;
|
||||
assert(nullptr != ts);
|
||||
size_t ts_sz = ts->size();
|
||||
WriteBatch batch(key.size() + ts_sz + value.size() + 24, /*max_bytes=*/0,
|
||||
ts_sz);
|
||||
Status s = batch.Put(column_family, key, value);
|
||||
if (!s.ok()) {
|
||||
return s;
|
||||
}
|
||||
WriteBatch batch(akey.size() + value.size() + 24);
|
||||
s = batch.Put(column_family, akey, value);
|
||||
s = batch.AssignTimestamp(*ts);
|
||||
if (!s.ok()) {
|
||||
return s;
|
||||
}
|
||||
|
||||
@ -159,9 +159,11 @@ void InternalKeyComparator::FindShortSuccessor(std::string* key) const {
|
||||
}
|
||||
}
|
||||
|
||||
LookupKey::LookupKey(const Slice& _user_key, SequenceNumber s) {
|
||||
LookupKey::LookupKey(const Slice& _user_key, SequenceNumber s,
|
||||
const Slice* ts) {
|
||||
size_t usize = _user_key.size();
|
||||
size_t needed = usize + 13; // A conservative estimate
|
||||
size_t ts_sz = (nullptr == ts) ? 0 : ts->size();
|
||||
size_t needed = usize + ts_sz + 13; // A conservative estimate
|
||||
char* dst;
|
||||
if (needed <= sizeof(space_)) {
|
||||
dst = space_;
|
||||
@ -170,10 +172,14 @@ LookupKey::LookupKey(const Slice& _user_key, SequenceNumber s) {
|
||||
}
|
||||
start_ = dst;
|
||||
// NOTE: We don't support users keys of more than 2GB :)
|
||||
dst = EncodeVarint32(dst, static_cast<uint32_t>(usize + 8));
|
||||
dst = EncodeVarint32(dst, static_cast<uint32_t>(usize + ts_sz + 8));
|
||||
kstart_ = dst;
|
||||
memcpy(dst, _user_key.data(), usize);
|
||||
dst += usize;
|
||||
if (nullptr != ts) {
|
||||
memcpy(dst, ts->data(), ts_sz);
|
||||
dst += ts_sz;
|
||||
}
|
||||
EncodeFixed64(dst, PackSequenceAndType(s, kValueTypeForSeek));
|
||||
dst += 8;
|
||||
end_ = dst;
|
||||
|
||||
@ -669,20 +669,4 @@ struct ParsedInternalKeyComparator {
|
||||
const InternalKeyComparator* cmp;
|
||||
};
|
||||
|
||||
// TODO (yanqin): this causes extra memory allocation and copy. Should be
|
||||
// addressed in the future.
|
||||
inline Status AppendTimestamp(const Slice& key, const Slice& timestamp,
|
||||
Slice* ret_key, std::string* ret_buf) {
|
||||
assert(ret_key != nullptr);
|
||||
assert(ret_buf != nullptr);
|
||||
if (key.data() + key.size() == timestamp.data()) {
|
||||
*ret_key = Slice(key.data(), key.size() + timestamp.size());
|
||||
} else {
|
||||
ret_buf->assign(key.data(), key.size());
|
||||
ret_buf->append(timestamp.data(), timestamp.size());
|
||||
*ret_key = Slice(*ret_buf);
|
||||
}
|
||||
return Status::OK();
|
||||
}
|
||||
|
||||
} // namespace rocksdb
|
||||
|
||||
@ -21,7 +21,8 @@ class LookupKey {
|
||||
public:
|
||||
// Initialize *this for looking up user_key at a snapshot with
|
||||
// the specified sequence number.
|
||||
LookupKey(const Slice& _user_key, SequenceNumber sequence);
|
||||
LookupKey(const Slice& _user_key, SequenceNumber sequence,
|
||||
const Slice* ts = nullptr);
|
||||
|
||||
~LookupKey();
|
||||
|
||||
|
||||
@ -135,6 +135,105 @@ struct BatchContentClassifier : public WriteBatch::Handler {
|
||||
}
|
||||
};
|
||||
|
||||
class TimestampAssigner : public WriteBatch::Handler {
|
||||
public:
|
||||
explicit TimestampAssigner(const Slice& ts)
|
||||
: timestamp_(ts), timestamps_(kEmptyTimestampList) {}
|
||||
explicit TimestampAssigner(const std::vector<Slice>& ts_list)
|
||||
: timestamps_(ts_list) {
|
||||
SanityCheck();
|
||||
}
|
||||
~TimestampAssigner() override {}
|
||||
|
||||
Status PutCF(uint32_t, const Slice& key, const Slice&) override {
|
||||
AssignTimestamp(key);
|
||||
++idx_;
|
||||
return Status::OK();
|
||||
}
|
||||
|
||||
Status DeleteCF(uint32_t, const Slice& key) override {
|
||||
AssignTimestamp(key);
|
||||
++idx_;
|
||||
return Status::OK();
|
||||
}
|
||||
|
||||
Status SingleDeleteCF(uint32_t, const Slice& key) override {
|
||||
AssignTimestamp(key);
|
||||
++idx_;
|
||||
return Status::OK();
|
||||
}
|
||||
|
||||
Status DeleteRangeCF(uint32_t, const Slice& begin_key,
|
||||
const Slice& end_key) override {
|
||||
AssignTimestamp(begin_key);
|
||||
AssignTimestamp(end_key);
|
||||
++idx_;
|
||||
return Status::OK();
|
||||
}
|
||||
|
||||
Status MergeCF(uint32_t, const Slice& key, const Slice&) override {
|
||||
AssignTimestamp(key);
|
||||
++idx_;
|
||||
return Status::OK();
|
||||
}
|
||||
|
||||
Status PutBlobIndexCF(uint32_t, const Slice&, const Slice&) override {
|
||||
// TODO (yanqin): support blob db in the future.
|
||||
return Status::OK();
|
||||
}
|
||||
|
||||
Status MarkBeginPrepare(bool) override {
|
||||
// TODO (yanqin): support in the future.
|
||||
return Status::OK();
|
||||
}
|
||||
|
||||
Status MarkEndPrepare(const Slice&) override {
|
||||
// TODO (yanqin): support in the future.
|
||||
return Status::OK();
|
||||
}
|
||||
|
||||
Status MarkCommit(const Slice&) override {
|
||||
// TODO (yanqin): support in the future.
|
||||
return Status::OK();
|
||||
}
|
||||
|
||||
Status MarkRollback(const Slice&) override {
|
||||
// TODO (yanqin): support in the future.
|
||||
return Status::OK();
|
||||
}
|
||||
|
||||
private:
|
||||
void SanityCheck() const {
|
||||
assert(!timestamps_.empty());
|
||||
#ifndef NDEBUG
|
||||
const size_t ts_sz = timestamps_[0].size();
|
||||
for (size_t i = 1; i != timestamps_.size(); ++i) {
|
||||
assert(ts_sz == timestamps_[i].size());
|
||||
}
|
||||
#endif // !NDEBUG
|
||||
}
|
||||
|
||||
void AssignTimestamp(const Slice& key) {
|
||||
assert(timestamps_.empty() || idx_ < timestamps_.size());
|
||||
const Slice& ts = timestamps_.empty() ? timestamp_ : timestamps_[idx_];
|
||||
size_t ts_sz = ts.size();
|
||||
char* ptr = const_cast<char*>(key.data() + key.size() - ts_sz);
|
||||
memcpy(ptr, ts.data(), ts_sz);
|
||||
}
|
||||
|
||||
static const std::vector<Slice> kEmptyTimestampList;
|
||||
const Slice timestamp_;
|
||||
const std::vector<Slice>& timestamps_;
|
||||
size_t idx_ = 0;
|
||||
|
||||
// No copy or move.
|
||||
TimestampAssigner(const TimestampAssigner&) = delete;
|
||||
TimestampAssigner(TimestampAssigner&&) = delete;
|
||||
TimestampAssigner& operator=(const TimestampAssigner&) = delete;
|
||||
TimestampAssigner&& operator=(TimestampAssigner&&) = delete;
|
||||
};
|
||||
const std::vector<Slice> TimestampAssigner::kEmptyTimestampList;
|
||||
|
||||
} // anon namespace
|
||||
|
||||
struct SavePoints {
|
||||
@ -142,7 +241,15 @@ struct SavePoints {
|
||||
};
|
||||
|
||||
WriteBatch::WriteBatch(size_t reserved_bytes, size_t max_bytes)
|
||||
: content_flags_(0), max_bytes_(max_bytes), rep_() {
|
||||
: content_flags_(0), max_bytes_(max_bytes), rep_(), timestamp_size_(0) {
|
||||
rep_.reserve((reserved_bytes > WriteBatchInternal::kHeader)
|
||||
? reserved_bytes
|
||||
: WriteBatchInternal::kHeader);
|
||||
rep_.resize(WriteBatchInternal::kHeader);
|
||||
}
|
||||
|
||||
WriteBatch::WriteBatch(size_t reserved_bytes, size_t max_bytes, size_t ts_sz)
|
||||
: content_flags_(0), max_bytes_(max_bytes), rep_(), timestamp_size_(ts_sz) {
|
||||
rep_.reserve((reserved_bytes > WriteBatchInternal::kHeader) ?
|
||||
reserved_bytes : WriteBatchInternal::kHeader);
|
||||
rep_.resize(WriteBatchInternal::kHeader);
|
||||
@ -151,18 +258,21 @@ WriteBatch::WriteBatch(size_t reserved_bytes, size_t max_bytes)
|
||||
WriteBatch::WriteBatch(const std::string& rep)
|
||||
: content_flags_(ContentFlags::DEFERRED),
|
||||
max_bytes_(0),
|
||||
rep_(rep) {}
|
||||
rep_(rep),
|
||||
timestamp_size_(0) {}
|
||||
|
||||
WriteBatch::WriteBatch(std::string&& rep)
|
||||
: content_flags_(ContentFlags::DEFERRED),
|
||||
max_bytes_(0),
|
||||
rep_(std::move(rep)) {}
|
||||
rep_(std::move(rep)),
|
||||
timestamp_size_(0) {}
|
||||
|
||||
WriteBatch::WriteBatch(const WriteBatch& src)
|
||||
: wal_term_point_(src.wal_term_point_),
|
||||
content_flags_(src.content_flags_.load(std::memory_order_relaxed)),
|
||||
max_bytes_(src.max_bytes_),
|
||||
rep_(src.rep_) {
|
||||
rep_(src.rep_),
|
||||
timestamp_size_(src.timestamp_size_) {
|
||||
if (src.save_points_ != nullptr) {
|
||||
save_points_.reset(new SavePoints());
|
||||
save_points_->stack = src.save_points_->stack;
|
||||
@ -174,7 +284,8 @@ WriteBatch::WriteBatch(WriteBatch&& src) noexcept
|
||||
wal_term_point_(std::move(src.wal_term_point_)),
|
||||
content_flags_(src.content_flags_.load(std::memory_order_relaxed)),
|
||||
max_bytes_(src.max_bytes_),
|
||||
rep_(std::move(src.rep_)) {}
|
||||
rep_(std::move(src.rep_)),
|
||||
timestamp_size_(src.timestamp_size_) {}
|
||||
|
||||
WriteBatch& WriteBatch::operator=(const WriteBatch& src) {
|
||||
if (&src != this) {
|
||||
@ -643,7 +754,14 @@ Status WriteBatchInternal::Put(WriteBatch* b, uint32_t column_family_id,
|
||||
b->rep_.push_back(static_cast<char>(kTypeColumnFamilyValue));
|
||||
PutVarint32(&b->rep_, column_family_id);
|
||||
}
|
||||
if (0 == b->timestamp_size_) {
|
||||
PutLengthPrefixedSlice(&b->rep_, key);
|
||||
} else {
|
||||
PutVarint32(&b->rep_,
|
||||
static_cast<uint32_t>(key.size() + b->timestamp_size_));
|
||||
b->rep_.append(key.data(), key.size());
|
||||
b->rep_.append(b->timestamp_size_, '\0');
|
||||
}
|
||||
PutLengthPrefixedSlice(&b->rep_, value);
|
||||
b->content_flags_.store(
|
||||
b->content_flags_.load(std::memory_order_relaxed) | ContentFlags::HAS_PUT,
|
||||
@ -692,7 +810,11 @@ Status WriteBatchInternal::Put(WriteBatch* b, uint32_t column_family_id,
|
||||
b->rep_.push_back(static_cast<char>(kTypeColumnFamilyValue));
|
||||
PutVarint32(&b->rep_, column_family_id);
|
||||
}
|
||||
if (0 == b->timestamp_size_) {
|
||||
PutLengthPrefixedSliceParts(&b->rep_, key);
|
||||
} else {
|
||||
PutLengthPrefixedSlicePartsWithPadding(&b->rep_, key, b->timestamp_size_);
|
||||
}
|
||||
PutLengthPrefixedSliceParts(&b->rep_, value);
|
||||
b->content_flags_.store(
|
||||
b->content_flags_.load(std::memory_order_relaxed) | ContentFlags::HAS_PUT,
|
||||
@ -1038,6 +1160,16 @@ Status WriteBatch::PopSavePoint() {
|
||||
return Status::OK();
|
||||
}
|
||||
|
||||
Status WriteBatch::AssignTimestamp(const Slice& ts) {
|
||||
TimestampAssigner ts_assigner(ts);
|
||||
return Iterate(&ts_assigner);
|
||||
}
|
||||
|
||||
Status WriteBatch::AssignTimestamps(const std::vector<Slice>& ts_list) {
|
||||
TimestampAssigner ts_assigner(ts_list);
|
||||
return Iterate(&ts_assigner);
|
||||
}
|
||||
|
||||
class MemTableInserter : public WriteBatch::Handler {
|
||||
|
||||
SequenceNumber sequence_;
|
||||
|
||||
@ -28,6 +28,7 @@
|
||||
#include <atomic>
|
||||
#include <memory>
|
||||
#include <string>
|
||||
#include <vector>
|
||||
#include "rocksdb/status.h"
|
||||
#include "rocksdb/write_batch_base.h"
|
||||
|
||||
@ -60,6 +61,7 @@ struct SavePoint {
|
||||
class WriteBatch : public WriteBatchBase {
|
||||
public:
|
||||
explicit WriteBatch(size_t reserved_bytes = 0, size_t max_bytes = 0);
|
||||
explicit WriteBatch(size_t reserved_bytes, size_t max_bytes, size_t ts_sz);
|
||||
~WriteBatch() override;
|
||||
|
||||
using WriteBatchBase::Put;
|
||||
@ -311,6 +313,12 @@ class WriteBatch : public WriteBatchBase {
|
||||
// Returns trie if MarkRollback will be called during Iterate
|
||||
bool HasRollback() const;
|
||||
|
||||
// Assign timestamp to write batch
|
||||
Status AssignTimestamp(const Slice& ts);
|
||||
|
||||
// Assign timestamps to write batch
|
||||
Status AssignTimestamps(const std::vector<Slice>& ts_list);
|
||||
|
||||
using WriteBatchBase::GetWriteBatch;
|
||||
WriteBatch* GetWriteBatch() override { return this; }
|
||||
|
||||
@ -361,6 +369,7 @@ class WriteBatch : public WriteBatchBase {
|
||||
|
||||
protected:
|
||||
std::string rep_; // See comment in write_batch.cc for the format of rep_
|
||||
const size_t timestamp_size_;
|
||||
|
||||
// Intentionally copyable
|
||||
};
|
||||
|
||||
@ -50,6 +50,8 @@ extern void PutVarint32Varint32Varint64(std::string* dst, uint32_t value1,
|
||||
extern void PutLengthPrefixedSlice(std::string* dst, const Slice& value);
|
||||
extern void PutLengthPrefixedSliceParts(std::string* dst,
|
||||
const SliceParts& slice_parts);
|
||||
extern void PutLengthPrefixedSlicePartsWithPadding(
|
||||
std::string* dst, const SliceParts& slice_parts, size_t pad_sz);
|
||||
|
||||
// Standard Get... routines parse a value from the beginning of a Slice
|
||||
// and advance the slice past the parsed value.
|
||||
@ -306,9 +308,8 @@ inline void PutLengthPrefixedSlice(std::string* dst, const Slice& value) {
|
||||
dst->append(value.data(), value.size());
|
||||
}
|
||||
|
||||
inline void PutLengthPrefixedSliceParts(std::string* dst,
|
||||
inline void PutLengthPrefixedSliceParts(std::string* dst, size_t total_bytes,
|
||||
const SliceParts& slice_parts) {
|
||||
size_t total_bytes = 0;
|
||||
for (int i = 0; i < slice_parts.num_parts; ++i) {
|
||||
total_bytes += slice_parts.parts[i].size();
|
||||
}
|
||||
@ -318,6 +319,17 @@ inline void PutLengthPrefixedSliceParts(std::string* dst,
|
||||
}
|
||||
}
|
||||
|
||||
inline void PutLengthPrefixedSliceParts(std::string* dst,
|
||||
const SliceParts& slice_parts) {
|
||||
PutLengthPrefixedSliceParts(dst, /*total_bytes=*/0, slice_parts);
|
||||
}
|
||||
|
||||
inline void PutLengthPrefixedSlicePartsWithPadding(
|
||||
std::string* dst, const SliceParts& slice_parts, size_t pad_sz) {
|
||||
PutLengthPrefixedSliceParts(dst, /*total_bytes=*/pad_sz, slice_parts);
|
||||
dst->append(pad_sz, '\0');
|
||||
}
|
||||
|
||||
inline int VarintLength(uint64_t v) {
|
||||
int len = 1;
|
||||
while (v >= 128) {
|
||||
|
||||
Loading…
Reference in New Issue
Block a user