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rocksdb/utilities/ttl/db_ttl.cc

291 lines
7.1 KiB

// 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 "utilities/ttl/db_ttl.h"
#include "include/utilities/utility_db.h"
#include "db/filename.h"
#include "util/coding.h"
#include "include/leveldb/env.h"
#include "include/leveldb/iterator.h"
namespace leveldb {
class TtlIterator : public Iterator {
public:
TtlIterator(Iterator* iter, int32_t ts_len)
: iter_(iter),
ts_len_(ts_len) {
assert(iter_);
}
~TtlIterator() {
delete iter_;
}
bool Valid() const {
return iter_->Valid();
}
void SeekToFirst() {
iter_->SeekToFirst();
}
void SeekToLast() {
iter_->SeekToLast();
}
void Seek(const Slice& target) {
iter_->Seek(target);
}
void Next() {
iter_->Next();
}
void Prev() {
iter_->Prev();
}
Slice key() const {
return iter_->key();
}
Slice value() const {
assert(DBWithTTL::SanityCheckTimestamp(iter_->value().ToString()).ok());
Slice trimmed_value = iter_->value();
trimmed_value.size_ -= ts_len_;
return trimmed_value;
}
Status status() const {
return iter_->status();
}
private:
Iterator* iter_;
int32_t ts_len_;
};
// Open the db inside DBWithTTL because options needs pointer to its ttl
DBWithTTL::DBWithTTL(const int32_t ttl,
const Options& options,
const std::string& dbname,
Status& st,
bool read_only)
: ttl_(ttl) {
assert(options.compaction_filter == nullptr);
Options options_to_open = options;
options_to_open.compaction_filter = this;
if (read_only) {
st = DB::OpenForReadOnly(options_to_open, dbname, &db_);
} else {
st = DB::Open(options_to_open, dbname, &db_);
}
}
DBWithTTL::~DBWithTTL() {
delete db_;
}
Status UtilityDB::OpenTtlDB(
const Options& options,
const std::string& dbname,
DB** dbptr,
int32_t ttl,
bool read_only) {
Status st;
*dbptr = new DBWithTTL(ttl, options, dbname, st, read_only);
if (!st.ok()) {
delete dbptr;
}
return st;
}
// returns true(i.e. key-value to be deleted) if its TS has expired based on ttl
bool DBWithTTL::Filter(
int level,
const Slice& key,
const Slice& old_val,
std::string* new_val,
bool* value_changed) const {
return IsStale(old_val, ttl_);
}
const char* DBWithTTL::Name() const {
return "Delete By TTL";
}
// Gives back the current time
Status DBWithTTL::GetCurrentTime(int32_t& curtime) {
return Env::Default()->GetCurrentTime((int64_t*)&curtime);
}
// Appends the current timestamp to the string.
// Returns false if could not get the current_time, true if append succeeds
Status DBWithTTL::AppendTS(const Slice& val, std::string& val_with_ts) {
val_with_ts.reserve(kTSLength + val.size());
char ts_string[kTSLength];
int32_t curtime;
Status st = GetCurrentTime(curtime);
if (!st.ok()) {
return st;
}
EncodeFixed32(ts_string, curtime);
val_with_ts.append(val.data(), val.size());
val_with_ts.append(ts_string, kTSLength);
return st;
}
// Returns corruption if the length of the string is lesser than timestamp, or
// timestamp refers to a time lesser than ttl-feature release time
Status DBWithTTL::SanityCheckTimestamp(const std::string& str) {
if (str.length() < (unsigned)kTSLength) {
return Status::Corruption("Error: value's length less than timestamp's\n");
}
// Checks that TS is not lesser than kMinTimestamp
// Gaurds against corruption & normal database opened incorrectly in ttl mode
int32_t timestamp_value =
DecodeFixed32(str.data() + str.size() - kTSLength);
if (timestamp_value < kMinTimestamp){
return Status::Corruption("Error: Timestamp < ttl feature release time!\n");
}
return Status::OK();
}
// Checks if the string is stale or not according to TTl provided
bool DBWithTTL::IsStale(const Slice& value, int32_t ttl) {
if (ttl <= 0) { // Data is fresh if TTL is non-positive
return false;
}
int32_t curtime;
if (!GetCurrentTime(curtime).ok()) {
return false; // Treat the data as fresh if could not get current time
} else {
int32_t timestamp_value =
DecodeFixed32(value.data() + value.size() - kTSLength);
if ((timestamp_value + ttl) < curtime) {
return true; // Data is stale
}
}
return false;
}
// Strips the TS from the end of the string
Status DBWithTTL::StripTS(std::string* str) {
Status st;
// Erasing characters which hold the TS
str->erase(str->length() - kTSLength, kTSLength);
return st;
}
Status DBWithTTL::Put(
const WriteOptions& o,
const Slice& key,
const Slice& val) {
std::string value_with_ts;
Status st = AppendTS(val, value_with_ts);
if (!st.ok()) {
return st;
}
return db_->Put(o, key, value_with_ts);
}
Status DBWithTTL::Get(const ReadOptions& options,
const Slice& key,
std::string* value) {
Status st = db_->Get(options, key, value);
if (!st.ok()) {
return st;
}
st = SanityCheckTimestamp(*value);
if (!st.ok()) {
return st;
}
return StripTS(value);
}
Status DBWithTTL::Delete(const WriteOptions& wopts, const Slice& key) {
return db_->Delete(wopts, key);
}
Status DBWithTTL::Merge(const WriteOptions& options,
const Slice& key,
const Slice& value) {
return Status::NotSupported("Merge operation not supported.");
}
Status DBWithTTL::Write(const WriteOptions& opts, WriteBatch* updates) {
return db_->Write(opts, updates);
}
Iterator* DBWithTTL::NewIterator(const ReadOptions& opts) {
return new TtlIterator(db_->NewIterator(opts), kTSLength);
}
const Snapshot* DBWithTTL::GetSnapshot() {
return db_->GetSnapshot();
}
void DBWithTTL::ReleaseSnapshot(const Snapshot* snapshot) {
db_->ReleaseSnapshot(snapshot);
}
bool DBWithTTL::GetProperty(const Slice& property, std::string* value) {
return db_->GetProperty(property, value);
}
void DBWithTTL::GetApproximateSizes(const Range* r, int n, uint64_t* sizes) {
db_->GetApproximateSizes(r, n, sizes);
}
void DBWithTTL::CompactRange(const Slice* begin, const Slice* end) {
db_->CompactRange(begin, end);
}
int DBWithTTL::NumberLevels() {
return db_->NumberLevels();
}
int DBWithTTL::MaxMemCompactionLevel() {
return db_->MaxMemCompactionLevel();
}
int DBWithTTL::Level0StopWriteTrigger() {
return db_->Level0StopWriteTrigger();
}
Status DBWithTTL::Flush(const FlushOptions& fopts) {
return db_->Flush(fopts);
}
Status DBWithTTL::DisableFileDeletions() {
return db_->DisableFileDeletions();
}
Status DBWithTTL::EnableFileDeletions() {
return db_->EnableFileDeletions();
}
Status DBWithTTL::GetLiveFiles(std::vector<std::string>& vec, uint64_t* mfs) {
return db_->GetLiveFiles(vec, mfs);
}
SequenceNumber DBWithTTL::GetLatestSequenceNumber() {
return db_->GetLatestSequenceNumber();
}
Status DBWithTTL::GetUpdatesSince(
SequenceNumber seq_number,
unique_ptr<TransactionLogIterator>* iter) {
return db_->GetUpdatesSince(seq_number, iter);
}
void DBWithTTL::TEST_Destroy_DBWithTtl() {
((DBImpl*) db_)->TEST_Destroy_DBImpl();
}
} // namespace leveldb