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rocksdb/trace_replay/trace_replay.cc

752 lines
24 KiB

// 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).
#include "trace_replay/trace_replay.h"
#include <chrono>
#include <sstream>
#include <thread>
#include "db/db_impl/db_impl.h"
#include "rocksdb/env.h"
#include "rocksdb/options.h"
#include "rocksdb/slice.h"
#include "rocksdb/system_clock.h"
#include "rocksdb/trace_reader_writer.h"
#include "rocksdb/write_batch.h"
#include "util/coding.h"
#include "util/string_util.h"
#include "util/threadpool_imp.h"
namespace ROCKSDB_NAMESPACE {
const std::string kTraceMagic = "feedcafedeadbeef";
namespace {
void DecodeCFAndKey(std::string& buffer, uint32_t* cf_id, Slice* key) {
Slice buf(buffer);
GetFixed32(&buf, cf_id);
GetLengthPrefixedSlice(&buf, key);
}
} // namespace
Status TracerHelper::ParseVersionStr(std::string& v_string, int* v_num) {
if (v_string.find_first_of('.') == std::string::npos ||
v_string.find_first_of('.') != v_string.find_last_of('.')) {
return Status::Corruption(
"Corrupted trace file. Incorrect version format.");
}
int tmp_num = 0;
for (int i = 0; i < static_cast<int>(v_string.size()); i++) {
if (v_string[i] == '.') {
continue;
} else if (isdigit(v_string[i])) {
tmp_num = tmp_num * 10 + (v_string[i] - '0');
} else {
return Status::Corruption(
"Corrupted trace file. Incorrect version format");
}
}
*v_num = tmp_num;
return Status::OK();
}
Status TracerHelper::ParseTraceHeader(const Trace& header, int* trace_version,
int* db_version) {
std::vector<std::string> s_vec;
int begin = 0, end;
for (int i = 0; i < 3; i++) {
assert(header.payload.find("\t", begin) != std::string::npos);
end = static_cast<int>(header.payload.find("\t", begin));
s_vec.push_back(header.payload.substr(begin, end - begin));
begin = end + 1;
}
std::string t_v_str, db_v_str;
assert(s_vec.size() == 3);
assert(s_vec[1].find("Trace Version: ") != std::string::npos);
t_v_str = s_vec[1].substr(15);
assert(s_vec[2].find("RocksDB Version: ") != std::string::npos);
db_v_str = s_vec[2].substr(17);
Status s;
s = ParseVersionStr(t_v_str, trace_version);
if (s != Status::OK()) {
return s;
}
s = ParseVersionStr(db_v_str, db_version);
return s;
}
void TracerHelper::EncodeTrace(const Trace& trace, std::string* encoded_trace) {
assert(encoded_trace);
PutFixed64(encoded_trace, trace.ts);
encoded_trace->push_back(trace.type);
PutFixed32(encoded_trace, static_cast<uint32_t>(trace.payload.size()));
encoded_trace->append(trace.payload);
}
Status TracerHelper::DecodeTrace(const std::string& encoded_trace,
Trace* trace) {
assert(trace != nullptr);
Slice enc_slice = Slice(encoded_trace);
if (!GetFixed64(&enc_slice, &trace->ts)) {
return Status::Incomplete("Decode trace string failed");
}
if (enc_slice.size() < kTraceTypeSize + kTracePayloadLengthSize) {
return Status::Incomplete("Decode trace string failed");
}
trace->type = static_cast<TraceType>(enc_slice[0]);
enc_slice.remove_prefix(kTraceTypeSize + kTracePayloadLengthSize);
trace->payload = enc_slice.ToString();
return Status::OK();
}
bool TracerHelper::SetPayloadMap(uint64_t& payload_map,
const TracePayloadType payload_type) {
uint64_t old_state = payload_map;
uint64_t tmp = 1;
payload_map |= (tmp << payload_type);
return old_state != payload_map;
}
void TracerHelper::DecodeWritePayload(Trace* trace,
WritePayload* write_payload) {
assert(write_payload != nullptr);
Slice buf(trace->payload);
GetFixed64(&buf, &trace->payload_map);
int64_t payload_map = static_cast<int64_t>(trace->payload_map);
while (payload_map) {
// Find the rightmost set bit.
uint32_t set_pos = static_cast<uint32_t>(log2(payload_map & -payload_map));
switch (set_pos) {
case TracePayloadType::kWriteBatchData:
GetLengthPrefixedSlice(&buf, &(write_payload->write_batch_data));
break;
default:
assert(false);
}
// unset the rightmost bit.
payload_map &= (payload_map - 1);
}
}
void TracerHelper::DecodeGetPayload(Trace* trace, GetPayload* get_payload) {
assert(get_payload != nullptr);
Slice buf(trace->payload);
GetFixed64(&buf, &trace->payload_map);
int64_t payload_map = static_cast<int64_t>(trace->payload_map);
while (payload_map) {
// Find the rightmost set bit.
uint32_t set_pos = static_cast<uint32_t>(log2(payload_map & -payload_map));
switch (set_pos) {
case TracePayloadType::kGetCFID:
GetFixed32(&buf, &(get_payload->cf_id));
break;
case TracePayloadType::kGetKey:
GetLengthPrefixedSlice(&buf, &(get_payload->get_key));
break;
default:
assert(false);
}
// unset the rightmost bit.
payload_map &= (payload_map - 1);
}
}
void TracerHelper::DecodeIterPayload(Trace* trace, IterPayload* iter_payload) {
assert(iter_payload != nullptr);
Slice buf(trace->payload);
GetFixed64(&buf, &trace->payload_map);
int64_t payload_map = static_cast<int64_t>(trace->payload_map);
while (payload_map) {
// Find the rightmost set bit.
uint32_t set_pos = static_cast<uint32_t>(log2(payload_map & -payload_map));
switch (set_pos) {
case TracePayloadType::kIterCFID:
GetFixed32(&buf, &(iter_payload->cf_id));
break;
case TracePayloadType::kIterKey:
GetLengthPrefixedSlice(&buf, &(iter_payload->iter_key));
break;
case TracePayloadType::kIterLowerBound:
GetLengthPrefixedSlice(&buf, &(iter_payload->lower_bound));
break;
case TracePayloadType::kIterUpperBound:
GetLengthPrefixedSlice(&buf, &(iter_payload->upper_bound));
break;
default:
assert(false);
}
// unset the rightmost bit.
payload_map &= (payload_map - 1);
}
}
Tracer::Tracer(const std::shared_ptr<SystemClock>& clock,
const TraceOptions& trace_options,
std::unique_ptr<TraceWriter>&& trace_writer)
: clock_(clock),
trace_options_(trace_options),
trace_writer_(std::move(trace_writer)),
trace_request_count_(0) {
// TODO: What if this fails?
WriteHeader().PermitUncheckedError();
}
Tracer::~Tracer() { trace_writer_.reset(); }
Status Tracer::Write(WriteBatch* write_batch) {
TraceType trace_type = kTraceWrite;
if (ShouldSkipTrace(trace_type)) {
return Status::OK();
}
Trace trace;
trace.ts = clock_->NowMicros();
trace.type = trace_type;
TracerHelper::SetPayloadMap(trace.payload_map,
TracePayloadType::kWriteBatchData);
PutFixed64(&trace.payload, trace.payload_map);
PutLengthPrefixedSlice(&trace.payload, Slice(write_batch->Data()));
return WriteTrace(trace);
}
Status Tracer::Get(ColumnFamilyHandle* column_family, const Slice& key) {
TraceType trace_type = kTraceGet;
if (ShouldSkipTrace(trace_type)) {
return Status::OK();
}
Trace trace;
trace.ts = clock_->NowMicros();
trace.type = trace_type;
// Set the payloadmap of the struct member that will be encoded in the
// payload.
TracerHelper::SetPayloadMap(trace.payload_map, TracePayloadType::kGetCFID);
TracerHelper::SetPayloadMap(trace.payload_map, TracePayloadType::kGetKey);
// Encode the Get struct members into payload. Make sure add them in order.
PutFixed64(&trace.payload, trace.payload_map);
PutFixed32(&trace.payload, column_family->GetID());
PutLengthPrefixedSlice(&trace.payload, key);
return WriteTrace(trace);
}
Status Tracer::IteratorSeek(const uint32_t& cf_id, const Slice& key,
const Slice& lower_bound, const Slice upper_bound) {
TraceType trace_type = kTraceIteratorSeek;
if (ShouldSkipTrace(trace_type)) {
return Status::OK();
}
Trace trace;
trace.ts = clock_->NowMicros();
trace.type = trace_type;
// Set the payloadmap of the struct member that will be encoded in the
// payload.
TracerHelper::SetPayloadMap(trace.payload_map, TracePayloadType::kIterCFID);
TracerHelper::SetPayloadMap(trace.payload_map, TracePayloadType::kIterKey);
if (lower_bound.size() > 0) {
TracerHelper::SetPayloadMap(trace.payload_map,
TracePayloadType::kIterLowerBound);
}
if (upper_bound.size() > 0) {
TracerHelper::SetPayloadMap(trace.payload_map,
TracePayloadType::kIterUpperBound);
}
// Encode the Iterator struct members into payload. Make sure add them in
// order.
PutFixed64(&trace.payload, trace.payload_map);
PutFixed32(&trace.payload, cf_id);
PutLengthPrefixedSlice(&trace.payload, key);
if (lower_bound.size() > 0) {
PutLengthPrefixedSlice(&trace.payload, lower_bound);
}
if (upper_bound.size() > 0) {
PutLengthPrefixedSlice(&trace.payload, upper_bound);
}
return WriteTrace(trace);
}
Status Tracer::IteratorSeekForPrev(const uint32_t& cf_id, const Slice& key,
const Slice& lower_bound,
const Slice upper_bound) {
TraceType trace_type = kTraceIteratorSeekForPrev;
if (ShouldSkipTrace(trace_type)) {
return Status::OK();
}
Trace trace;
trace.ts = clock_->NowMicros();
trace.type = trace_type;
// Set the payloadmap of the struct member that will be encoded in the
// payload.
TracerHelper::SetPayloadMap(trace.payload_map, TracePayloadType::kIterCFID);
TracerHelper::SetPayloadMap(trace.payload_map, TracePayloadType::kIterKey);
if (lower_bound.size() > 0) {
TracerHelper::SetPayloadMap(trace.payload_map,
TracePayloadType::kIterLowerBound);
}
if (upper_bound.size() > 0) {
TracerHelper::SetPayloadMap(trace.payload_map,
TracePayloadType::kIterUpperBound);
}
// Encode the Iterator struct members into payload. Make sure add them in
// order.
PutFixed64(&trace.payload, trace.payload_map);
PutFixed32(&trace.payload, cf_id);
PutLengthPrefixedSlice(&trace.payload, key);
if (lower_bound.size() > 0) {
PutLengthPrefixedSlice(&trace.payload, lower_bound);
}
if (upper_bound.size() > 0) {
PutLengthPrefixedSlice(&trace.payload, upper_bound);
}
return WriteTrace(trace);
}
bool Tracer::ShouldSkipTrace(const TraceType& trace_type) {
if (IsTraceFileOverMax()) {
return true;
}
if ((trace_options_.filter & kTraceFilterGet
&& trace_type == kTraceGet)
|| (trace_options_.filter & kTraceFilterWrite
&& trace_type == kTraceWrite)) {
return true;
}
++trace_request_count_;
if (trace_request_count_ < trace_options_.sampling_frequency) {
return true;
}
trace_request_count_ = 0;
return false;
}
bool Tracer::IsTraceFileOverMax() {
uint64_t trace_file_size = trace_writer_->GetFileSize();
return (trace_file_size > trace_options_.max_trace_file_size);
}
Status Tracer::WriteHeader() {
std::ostringstream s;
s << kTraceMagic << "\t"
<< "Trace Version: " << kTraceFileMajorVersion << "."
<< kTraceFileMinorVersion << "\t"
<< "RocksDB Version: " << kMajorVersion << "." << kMinorVersion << "\t"
<< "Format: Timestamp OpType Payload\n";
std::string header(s.str());
Trace trace;
trace.ts = clock_->NowMicros();
trace.type = kTraceBegin;
trace.payload = header;
return WriteTrace(trace);
}
Status Tracer::WriteFooter() {
Trace trace;
trace.ts = clock_->NowMicros();
trace.type = kTraceEnd;
TracerHelper::SetPayloadMap(trace.payload_map,
TracePayloadType::kEmptyPayload);
trace.payload = "";
return WriteTrace(trace);
}
Status Tracer::WriteTrace(const Trace& trace) {
std::string encoded_trace;
TracerHelper::EncodeTrace(trace, &encoded_trace);
return trace_writer_->Write(Slice(encoded_trace));
}
Status Tracer::Close() { return WriteFooter(); }
Replayer::Replayer(DB* db, const std::vector<ColumnFamilyHandle*>& handles,
std::unique_ptr<TraceReader>&& reader)
: trace_reader_(std::move(reader)) {
assert(db != nullptr);
db_ = static_cast<DBImpl*>(db->GetRootDB());
env_ = Env::Default();
for (ColumnFamilyHandle* cfh : handles) {
cf_map_[cfh->GetID()] = cfh;
}
fast_forward_ = 1;
}
Replayer::~Replayer() { trace_reader_.reset(); }
Status Replayer::SetFastForward(uint32_t fast_forward) {
Status s;
if (fast_forward < 1) {
s = Status::InvalidArgument("Wrong fast forward speed!");
} else {
fast_forward_ = fast_forward;
s = Status::OK();
}
return s;
}
Status Replayer::Replay() {
Status s;
Trace header;
int db_version;
s = ReadHeader(&header);
if (!s.ok()) {
return s;
}
s = TracerHelper::ParseTraceHeader(header, &trace_file_version_, &db_version);
if (!s.ok()) {
return s;
}
std::chrono::system_clock::time_point replay_epoch =
std::chrono::system_clock::now();
WriteOptions woptions;
ReadOptions roptions;
Trace trace;
uint64_t ops = 0;
Iterator* single_iter = nullptr;
while (s.ok()) {
trace.reset();
s = ReadTrace(&trace);
if (!s.ok()) {
break;
}
std::this_thread::sleep_until(
replay_epoch +
std::chrono::microseconds((trace.ts - header.ts) / fast_forward_));
if (trace.type == kTraceWrite) {
if (trace_file_version_ < 2) {
WriteBatch batch(trace.payload);
db_->Write(woptions, &batch);
} else {
WritePayload w_payload;
TracerHelper::DecodeWritePayload(&trace, &w_payload);
WriteBatch batch(w_payload.write_batch_data.ToString());
db_->Write(woptions, &batch);
}
ops++;
} else if (trace.type == kTraceGet) {
GetPayload get_payload;
get_payload.get_key = 0;
if (trace_file_version_ < 2) {
DecodeCFAndKey(trace.payload, &get_payload.cf_id, &get_payload.get_key);
} else {
TracerHelper::DecodeGetPayload(&trace, &get_payload);
}
if (get_payload.cf_id > 0 &&
cf_map_.find(get_payload.cf_id) == cf_map_.end()) {
return Status::Corruption("Invalid Column Family ID.");
}
std::string value;
if (get_payload.cf_id == 0) {
db_->Get(roptions, get_payload.get_key, &value);
} else {
db_->Get(roptions, cf_map_[get_payload.cf_id], get_payload.get_key,
&value);
}
ops++;
} else if (trace.type == kTraceIteratorSeek) {
// Currently, we only support to call Seek. The Next() and Prev() is not
// supported.
IterPayload iter_payload;
iter_payload.cf_id = 0;
if (trace_file_version_ < 2) {
DecodeCFAndKey(trace.payload, &iter_payload.cf_id,
&iter_payload.iter_key);
} else {
TracerHelper::DecodeIterPayload(&trace, &iter_payload);
}
if (iter_payload.cf_id > 0 &&
cf_map_.find(iter_payload.cf_id) == cf_map_.end()) {
return Status::Corruption("Invalid Column Family ID.");
}
if (iter_payload.cf_id == 0) {
single_iter = db_->NewIterator(roptions);
} else {
single_iter = db_->NewIterator(roptions, cf_map_[iter_payload.cf_id]);
}
single_iter->Seek(iter_payload.iter_key);
ops++;
delete single_iter;
} else if (trace.type == kTraceIteratorSeekForPrev) {
// Currently, we only support to call SeekForPrev. The Next() and Prev()
// is not supported.
IterPayload iter_payload;
iter_payload.cf_id = 0;
if (trace_file_version_ < 2) {
DecodeCFAndKey(trace.payload, &iter_payload.cf_id,
&iter_payload.iter_key);
} else {
TracerHelper::DecodeIterPayload(&trace, &iter_payload);
}
if (iter_payload.cf_id > 0 &&
cf_map_.find(iter_payload.cf_id) == cf_map_.end()) {
return Status::Corruption("Invalid Column Family ID.");
}
if (iter_payload.cf_id == 0) {
single_iter = db_->NewIterator(roptions);
} else {
single_iter = db_->NewIterator(roptions, cf_map_[iter_payload.cf_id]);
}
single_iter->SeekForPrev(iter_payload.iter_key);
ops++;
delete single_iter;
} else if (trace.type == kTraceEnd) {
// Do nothing for now.
// TODO: Add some validations later.
break;
}
}
if (s.IsIncomplete()) {
// Reaching eof returns Incomplete status at the moment.
// Could happen when killing a process without calling EndTrace() API.
// TODO: Add better error handling.
return Status::OK();
}
return s;
}
// The trace can be replayed with multithread by configurnge the number of
// threads in the thread pool. Trace records are read from the trace file
// sequentially and the corresponding queries are scheduled in the task
// queue based on the timestamp. Currently, we support Write_batch (Put,
// Delete, SingleDelete, DeleteRange), Get, Iterator (Seek and SeekForPrev).
Status Replayer::MultiThreadReplay(uint32_t threads_num) {
Status s;
Trace header;
int db_version;
s = ReadHeader(&header);
if (!s.ok()) {
return s;
}
s = TracerHelper::ParseTraceHeader(header, &trace_file_version_, &db_version);
if (!s.ok()) {
return s;
}
ThreadPoolImpl thread_pool;
thread_pool.SetHostEnv(env_);
if (threads_num > 1) {
thread_pool.SetBackgroundThreads(static_cast<int>(threads_num));
} else {
thread_pool.SetBackgroundThreads(1);
}
std::chrono::system_clock::time_point replay_epoch =
std::chrono::system_clock::now();
WriteOptions woptions;
ReadOptions roptions;
uint64_t ops = 0;
while (s.ok()) {
std::unique_ptr<ReplayerWorkerArg> ra(new ReplayerWorkerArg);
ra->db = db_;
s = ReadTrace(&(ra->trace_entry));
if (!s.ok()) {
break;
}
ra->cf_map = &cf_map_;
ra->woptions = woptions;
ra->roptions = roptions;
ra->trace_file_version = trace_file_version_;
std::this_thread::sleep_until(
replay_epoch + std::chrono::microseconds(
(ra->trace_entry.ts - header.ts) / fast_forward_));
if (ra->trace_entry.type == kTraceWrite) {
thread_pool.Schedule(&Replayer::BGWorkWriteBatch, ra.release(), nullptr,
nullptr);
ops++;
} else if (ra->trace_entry.type == kTraceGet) {
thread_pool.Schedule(&Replayer::BGWorkGet, ra.release(), nullptr,
nullptr);
ops++;
} else if (ra->trace_entry.type == kTraceIteratorSeek) {
thread_pool.Schedule(&Replayer::BGWorkIterSeek, ra.release(), nullptr,
nullptr);
ops++;
} else if (ra->trace_entry.type == kTraceIteratorSeekForPrev) {
thread_pool.Schedule(&Replayer::BGWorkIterSeekForPrev, ra.release(),
nullptr, nullptr);
ops++;
} else if (ra->trace_entry.type == kTraceEnd) {
// Do nothing for now.
// TODO: Add some validations later.
break;
} else {
// Other trace entry types that are not implemented for replay.
// To finish the replay, we continue the process.
continue;
}
}
if (s.IsIncomplete()) {
// Reaching eof returns Incomplete status at the moment.
// Could happen when killing a process without calling EndTrace() API.
// TODO: Add better error handling.
s = Status::OK();
}
thread_pool.JoinAllThreads();
return s;
}
Status Replayer::ReadHeader(Trace* header) {
assert(header != nullptr);
std::string encoded_trace;
// Read the trace head
Status s = trace_reader_->Read(&encoded_trace);
if (!s.ok()) {
return s;
}
s = TracerHelper::DecodeTrace(encoded_trace, header);
if (header->type != kTraceBegin) {
return Status::Corruption("Corrupted trace file. Incorrect header.");
}
if (header->payload.substr(0, kTraceMagic.length()) != kTraceMagic) {
return Status::Corruption("Corrupted trace file. Incorrect magic.");
}
return s;
}
Status Replayer::ReadFooter(Trace* footer) {
assert(footer != nullptr);
Status s = ReadTrace(footer);
if (!s.ok()) {
return s;
}
if (footer->type != kTraceEnd) {
return Status::Corruption("Corrupted trace file. Incorrect footer.");
}
// TODO: Add more validations later
return s;
}
Status Replayer::ReadTrace(Trace* trace) {
assert(trace != nullptr);
std::string encoded_trace;
Status s = trace_reader_->Read(&encoded_trace);
if (!s.ok()) {
return s;
}
return TracerHelper::DecodeTrace(encoded_trace, trace);
}
void Replayer::BGWorkGet(void* arg) {
std::unique_ptr<ReplayerWorkerArg> ra(
reinterpret_cast<ReplayerWorkerArg*>(arg));
assert(ra != nullptr);
auto cf_map = static_cast<std::unordered_map<uint32_t, ColumnFamilyHandle*>*>(
ra->cf_map);
GetPayload get_payload;
get_payload.cf_id = 0;
if (ra->trace_file_version < 2) {
DecodeCFAndKey(ra->trace_entry.payload, &get_payload.cf_id,
&get_payload.get_key);
} else {
TracerHelper::DecodeGetPayload(&(ra->trace_entry), &get_payload);
}
if (get_payload.cf_id > 0 &&
cf_map->find(get_payload.cf_id) == cf_map->end()) {
return;
}
std::string value;
if (get_payload.cf_id == 0) {
ra->db->Get(ra->roptions, get_payload.get_key, &value);
} else {
ra->db->Get(ra->roptions, (*cf_map)[get_payload.cf_id], get_payload.get_key,
&value);
}
return;
}
void Replayer::BGWorkWriteBatch(void* arg) {
std::unique_ptr<ReplayerWorkerArg> ra(
reinterpret_cast<ReplayerWorkerArg*>(arg));
assert(ra != nullptr);
if (ra->trace_file_version < 2) {
WriteBatch batch(ra->trace_entry.payload);
ra->db->Write(ra->woptions, &batch);
} else {
WritePayload w_payload;
TracerHelper::DecodeWritePayload(&(ra->trace_entry), &w_payload);
WriteBatch batch(w_payload.write_batch_data.ToString());
ra->db->Write(ra->woptions, &batch);
}
return;
}
void Replayer::BGWorkIterSeek(void* arg) {
std::unique_ptr<ReplayerWorkerArg> ra(
reinterpret_cast<ReplayerWorkerArg*>(arg));
assert(ra != nullptr);
auto cf_map = static_cast<std::unordered_map<uint32_t, ColumnFamilyHandle*>*>(
ra->cf_map);
IterPayload iter_payload;
iter_payload.cf_id = 0;
if (ra->trace_file_version < 2) {
DecodeCFAndKey(ra->trace_entry.payload, &iter_payload.cf_id,
&iter_payload.iter_key);
} else {
TracerHelper::DecodeIterPayload(&(ra->trace_entry), &iter_payload);
}
if (iter_payload.cf_id > 0 &&
cf_map->find(iter_payload.cf_id) == cf_map->end()) {
return;
}
Iterator* single_iter = nullptr;
if (iter_payload.cf_id == 0) {
single_iter = ra->db->NewIterator(ra->roptions);
} else {
single_iter =
ra->db->NewIterator(ra->roptions, (*cf_map)[iter_payload.cf_id]);
}
single_iter->Seek(iter_payload.iter_key);
delete single_iter;
return;
}
void Replayer::BGWorkIterSeekForPrev(void* arg) {
std::unique_ptr<ReplayerWorkerArg> ra(
reinterpret_cast<ReplayerWorkerArg*>(arg));
assert(ra != nullptr);
auto cf_map = static_cast<std::unordered_map<uint32_t, ColumnFamilyHandle*>*>(
ra->cf_map);
IterPayload iter_payload;
iter_payload.cf_id = 0;
if (ra->trace_file_version < 2) {
DecodeCFAndKey(ra->trace_entry.payload, &iter_payload.cf_id,
&iter_payload.iter_key);
} else {
TracerHelper::DecodeIterPayload(&(ra->trace_entry), &iter_payload);
}
if (iter_payload.cf_id > 0 &&
cf_map->find(iter_payload.cf_id) == cf_map->end()) {
return;
}
Iterator* single_iter = nullptr;
if (iter_payload.cf_id == 0) {
single_iter = ra->db->NewIterator(ra->roptions);
} else {
single_iter =
ra->db->NewIterator(ra->roptions, (*cf_map)[iter_payload.cf_id]);
}
single_iter->SeekForPrev(iter_payload.iter_key);
delete single_iter;
return;
}
} // namespace ROCKSDB_NAMESPACE