/usr/include/rocksdb/utilities/db_ttl.h is in librocksdb-dev 4.5.1-2.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
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// 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 "rocksdb/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
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