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rocksdb/utilities/ttl/db_ttl.h

360 lines
10 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.
#pragma once
#include "rocksdb/db.h"
#include "rocksdb/env.h"
#include "rocksdb/compaction_filter.h"
#include "rocksdb/merge_operator.h"
#include "utilities/utility_db.h"
#include "db/db_impl.h"
namespace rocksdb {
class DBWithTTL : public StackableDB {
public:
DBWithTTL(const int32_t ttl,
const Options& options,
const std::string& dbname,
Status& st,
bool read_only);
virtual ~DBWithTTL();
virtual Status Put(const WriteOptions& o,
const Slice& key,
const Slice& val);
virtual Status Get(const ReadOptions& options,
const Slice& key,
std::string* value);
virtual std::vector<Status> MultiGet(const ReadOptions& options,
const std::vector<Slice>& keys,
std::vector<std::string>* values);
virtual bool KeyMayExist(const ReadOptions& options,
const Slice& key,
std::string* value,
bool* value_found = nullptr) override;
virtual Status Delete(const WriteOptions& wopts, const Slice& key);
virtual Status Merge(const WriteOptions& options,
const Slice& key,
const Slice& value);
virtual Status Write(const WriteOptions& opts, WriteBatch* updates);
virtual Iterator* NewIterator(const ReadOptions& opts);
virtual const Snapshot* GetSnapshot();
virtual void ReleaseSnapshot(const Snapshot* snapshot);
virtual bool GetProperty(const Slice& property, std::string* value);
virtual void GetApproximateSizes(const Range* r, int n, uint64_t* sizes);
virtual void CompactRange(const Slice* begin, const Slice* end,
bool reduce_level = false, int target_level = -1);
virtual int NumberLevels();
virtual int MaxMemCompactionLevel();
virtual int Level0StopWriteTrigger();
virtual Status Flush(const FlushOptions& fopts);
virtual Status DisableFileDeletions();
virtual Status EnableFileDeletions();
virtual Status GetLiveFiles(std::vector<std::string>& vec, uint64_t* mfs,
bool flush_memtable = true);
virtual Status GetSortedWalFiles(VectorLogPtr& files);
virtual Status DeleteFile(std::string name);
virtual SequenceNumber GetLatestSequenceNumber();
virtual Status GetUpdatesSince(SequenceNumber seq_number,
unique_ptr<TransactionLogIterator>* iter);
// Simulate a db crash, no elegant closing of database.
void TEST_Destroy_DBWithTtl();
virtual DB* GetRawDB() {
return db_;
}
static bool IsStale(const Slice& value, int32_t ttl);
static Status AppendTS(const Slice& val, std::string& val_with_ts);
static Status SanityCheckTimestamp(const Slice& str);
static Status StripTS(std::string* str);
static Status GetCurrentTime(int32_t& curtime);
static const uint32_t kTSLength = sizeof(int32_t); // size of timestamp
static const int32_t kMinTimestamp = 1368146402; // 05/09/2013:5:40PM GMT-8
static const int32_t kMaxTimestamp = 2147483647; // 01/18/2038:7:14PM GMT-8
private:
DB* db_;
int32_t ttl_;
unique_ptr<CompactionFilter> ttl_comp_filter_;
};
class TtlIterator : public Iterator {
public:
explicit TtlIterator(Iterator* iter)
: iter_(iter) {
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();
}
int32_t timestamp() const {
return DecodeFixed32(
iter_->value().data() + iter_->value().size() - DBWithTTL::kTSLength);
}
Slice value() const {
//TODO: handle timestamp corruption like in general iterator semantics
assert(DBWithTTL::SanityCheckTimestamp(iter_->value()).ok());
Slice trimmed_value = iter_->value();
trimmed_value.size_ -= DBWithTTL::kTSLength;
return trimmed_value;
}
Status status() const {
return iter_->status();
}
private:
Iterator* iter_;
};
class TtlCompactionFilter : public CompactionFilter {
public:
TtlCompactionFilter(
int32_t ttl,
const CompactionFilter* user_comp_filter,
std::unique_ptr<const CompactionFilter>
user_comp_filter_from_factory = nullptr)
: ttl_(ttl),
user_comp_filter_(user_comp_filter),
user_comp_filter_from_factory_(std::move(user_comp_filter_from_factory)) {
// Unlike the merge operator, compaction filter is necessary for TTL, hence
// this would be called even if user doesn't specify any compaction-filter
if (!user_comp_filter_) {
user_comp_filter_ = user_comp_filter_from_factory_.get();
}
}
virtual bool Filter(int level,
const Slice& key,
const Slice& old_val,
std::string* new_val,
bool* value_changed) const override {
if (DBWithTTL::IsStale(old_val, ttl_)) {
return true;
}
if (user_comp_filter_ == nullptr) {
return false;
}
assert(old_val.size() >= DBWithTTL::kTSLength);
Slice old_val_without_ts(old_val.data(),
old_val.size() - DBWithTTL::kTSLength);
if (user_comp_filter_->Filter(level, key, old_val_without_ts, new_val,
value_changed)) {
return true;
}
if (*value_changed) {
new_val->append(old_val.data() + old_val.size() - DBWithTTL::kTSLength,
DBWithTTL::kTSLength);
}
return false;
}
virtual const char* Name() const override {
return "Delete By TTL";
}
private:
int32_t ttl_;
const CompactionFilter* user_comp_filter_;
std::unique_ptr<const CompactionFilter> user_comp_filter_from_factory_;
};
class TtlCompactionFilterFactory : public CompactionFilterFactory {
public:
TtlCompactionFilterFactory(
int32_t ttl,
std::shared_ptr<CompactionFilterFactory> comp_filter_factory)
: ttl_(ttl),
user_comp_filter_factory_(comp_filter_factory) { }
virtual std::unique_ptr<CompactionFilter> CreateCompactionFilter() {
return std::unique_ptr<TtlCompactionFilter>(
new TtlCompactionFilter(
ttl_,
nullptr,
std::move(user_comp_filter_factory_->CreateCompactionFilter())));
}
virtual const char* Name() const override {
return "TtlCompactionFilterFactory";
}
private:
int32_t ttl_;
std::shared_ptr<CompactionFilterFactory> user_comp_filter_factory_;
};
class TtlMergeOperator : public MergeOperator {
public:
explicit TtlMergeOperator(const std::shared_ptr<MergeOperator> merge_op)
: user_merge_op_(merge_op) {
assert(merge_op);
}
virtual bool FullMerge(const Slice& key,
const Slice* existing_value,
const std::deque<std::string>& operands,
std::string* new_value,
Logger* logger) const override {
const uint32_t ts_len = DBWithTTL::kTSLength;
if (existing_value && existing_value->size() < ts_len) {
Log(logger, "Error: Could not remove timestamp from existing value.");
return false;
}
// Extract time-stamp from each operand to be passed to user_merge_op_
std::deque<std::string> operands_without_ts;
for (const auto &operand : operands) {
if (operand.size() < ts_len) {
Log(logger, "Error: Could not remove timestamp from operand value.");
return false;
}
operands_without_ts.push_back(operand.substr(0, operand.size() - ts_len));
}
// Apply the user merge operator (store result in *new_value)
bool good = true;
if (existing_value) {
Slice existing_value_without_ts(existing_value->data(),
existing_value->size() - ts_len);
good = user_merge_op_->FullMerge(key, &existing_value_without_ts,
operands_without_ts, new_value, logger);
} else {
good = user_merge_op_->FullMerge(key, nullptr, operands_without_ts,
new_value, logger);
}
// Return false if the user merge operator returned false
if (!good) {
return false;
}
// Augment the *new_value with the ttl time-stamp
int32_t curtime;
if (!DBWithTTL::GetCurrentTime(curtime).ok()) {
Log(logger, "Error: Could not get current time to be attached internally "
"to the new value.");
return false;
} else {
char ts_string[ts_len];
EncodeFixed32(ts_string, curtime);
new_value->append(ts_string, ts_len);
return true;
}
}
virtual bool PartialMerge(const Slice& key,
const Slice& left_operand,
const Slice& right_operand,
std::string* new_value,
Logger* logger) const override {
const uint32_t ts_len = DBWithTTL::kTSLength;
if (left_operand.size() < ts_len || right_operand.size() < ts_len) {
Log(logger, "Error: Could not remove timestamp from value.");
return false;
}
// Apply the user partial-merge operator (store result in *new_value)
assert(new_value);
Slice left_without_ts(left_operand.data(), left_operand.size() - ts_len);
Slice right_without_ts(right_operand.data(), right_operand.size() - ts_len);
if (!user_merge_op_->PartialMerge(key, left_without_ts, right_without_ts,
new_value, logger)) {
return false;
}
// Augment the *new_value with the ttl time-stamp
int32_t curtime;
if (!DBWithTTL::GetCurrentTime(curtime).ok()) {
Log(logger, "Error: Could not get current time to be attached internally "
"to the new value.");
return false;
} else {
char ts_string[ts_len];
EncodeFixed32(ts_string, curtime);
new_value->append(ts_string, ts_len);
return true;
}
}
virtual const char* Name() const override {
return "Merge By TTL";
}
private:
std::shared_ptr<MergeOperator> user_merge_op_;
};
}