mirror of https://github.com/facebook/rocksdb.git
69 lines
2.7 KiB
C
69 lines
2.7 KiB
C
|
// Copyright (c) 2013, Facebook, Inc. All rights reserved.
|
||
|
|
// This source code is licensed under the BSD-style license found in the
|
||
|
|
// LICENSE file in the root directory of this source tree. An additional grant
|
||
|
|
// of patent rights can be found in the PATENTS file in the same directory.
|
||
|
|
|
||
|
|
#pragma once
|
||
|
|
#ifndef ROCKSDB_LITE
|
||
|
|
|
||
|
|
#include <string>
|
||
|
|
#include <vector>
|
||
|
|
|
||
|
|
#include "utilities/stackable_db.h"
|
||
|
|
#include "rocksdb/db.h"
|
||
|
|
|
||
|
|
namespace rocksdb {
|
||
|
|
|
||
|
|
// Database with TTL support.
|
||
|
|
//
|
||
|
|
// USE-CASES:
|
||
|
|
// This API should be used to open the db when key-values inserted are
|
||
|
|
// meant to be removed from the db in a non-strict 'ttl' amount of time
|
||
|
|
// Therefore, this guarantees that key-values inserted will remain in the
|
||
|
|
// db for >= ttl amount of time and the db will make efforts to remove the
|
||
|
|
// key-values as soon as possible after ttl seconds of their insertion.
|
||
|
|
//
|
||
|
|
// BEHAVIOUR:
|
||
|
|
// TTL is accepted in seconds
|
||
|
|
// (int32_t)Timestamp(creation) is suffixed to values in Put internally
|
||
|
|
// Expired TTL values deleted in compaction only:(Timestamp+ttl<time_now)
|
||
|
|
// Get/Iterator may return expired entries(compaction not run on them yet)
|
||
|
|
// Different TTL may be used during different Opens
|
||
|
|
// Example: Open1 at t=0 with ttl=4 and insert k1,k2, close at t=2
|
||
|
|
// Open2 at t=3 with ttl=5. Now k1,k2 should be deleted at t>=5
|
||
|
|
// read_only=true opens in the usual read-only mode. Compactions will not be
|
||
|
|
// triggered(neither manual nor automatic), so no expired entries removed
|
||
|
|
//
|
||
|
|
// CONSTRAINTS:
|
||
|
|
// Not specifying/passing or non-positive TTL behaves like TTL = infinity
|
||
|
|
//
|
||
|
|
// !!!WARNING!!!:
|
||
|
|
// Calling DB::Open directly to re-open a db created by this API will get
|
||
|
|
// corrupt values(timestamp suffixed) and no ttl effect will be there
|
||
|
|
// during the second Open, so use this API consistently to open the db
|
||
|
|
// Be careful when passing ttl with a small positive value because the
|
||
|
|
// whole database may be deleted in a small amount of time
|
||
|
|
|
||
|
|
class DBWithTTL : public StackableDB {
|
||
|
|
public:
|
||
|
|
virtual Status CreateColumnFamilyWithTtl(
|
||
|
|
const ColumnFamilyOptions& options, const std::string& column_family_name,
|
||
|
|
ColumnFamilyHandle** handle, int ttl) = 0;
|
||
|
|
|
||
|
|
static Status Open(const Options& options, const std::string& dbname,
|
||
|
|
DBWithTTL** dbptr, int32_t ttl = 0,
|
||
|
|
bool read_only = false);
|
||
|
|
|
||
|
|
static Status Open(const DBOptions& db_options, const std::string& dbname,
|
||
|
|
const std::vector<ColumnFamilyDescriptor>& column_families,
|
||
|
|
std::vector<ColumnFamilyHandle*>* handles,
|
||
|
|
DBWithTTL** dbptr, std::vector<int32_t> ttls,
|
||
|
|
bool read_only = false);
|
||
|
|
|
||
|
|
protected:
|
||
|
|
explicit DBWithTTL(DB* db) : StackableDB(db) {}
|
||
|
|
};
|
||
|
|
|
||
|
|
} // namespace rocksdb
|
||
|
|
#endif // ROCKSDB_LITE
|