/Users/deen/code/yugabyte-db/src/yb/rocksdb/utilities/db_ttl.h
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1 | | // Copyright (c) 2011-present, Facebook, Inc. All rights reserved. |
2 | | // This source code is licensed under the BSD-style license found in the |
3 | | // LICENSE file in the root directory of this source tree. An additional grant |
4 | | // of patent rights can be found in the PATENTS file in the same directory. |
5 | | // |
6 | | // The following only applies to changes made to this file as part of YugaByte development. |
7 | | // |
8 | | // Portions Copyright (c) YugaByte, Inc. |
9 | | // |
10 | | // Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except |
11 | | // in compliance with the License. You may obtain a copy of the License at |
12 | | // |
13 | | // http://www.apache.org/licenses/LICENSE-2.0 |
14 | | // |
15 | | // Unless required by applicable law or agreed to in writing, software distributed under the License |
16 | | // is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express |
17 | | // or implied. See the License for the specific language governing permissions and limitations |
18 | | // under the License. |
19 | | // |
20 | | |
21 | | #pragma once |
22 | | #ifndef ROCKSDB_LITE |
23 | | |
24 | | #include <string> |
25 | | #include <vector> |
26 | | |
27 | | #include "yb/rocksdb/utilities/stackable_db.h" |
28 | | #include "yb/rocksdb/db.h" |
29 | | |
30 | | namespace rocksdb { |
31 | | |
32 | | // Database with TTL support. |
33 | | // |
34 | | // USE-CASES: |
35 | | // This API should be used to open the db when key-values inserted are |
36 | | // meant to be removed from the db in a non-strict 'ttl' amount of time |
37 | | // Therefore, this guarantees that key-values inserted will remain in the |
38 | | // db for >= ttl amount of time and the db will make efforts to remove the |
39 | | // key-values as soon as possible after ttl seconds of their insertion. |
40 | | // |
41 | | // BEHAVIOUR: |
42 | | // TTL is accepted in seconds |
43 | | // (int32_t)Timestamp(creation) is suffixed to values in Put internally |
44 | | // Expired TTL values deleted in compaction only:(Timestamp+ttl<time_now) |
45 | | // Get/Iterator may return expired entries(compaction not run on them yet) |
46 | | // Different TTL may be used during different Opens |
47 | | // Example: Open1 at t=0 with ttl=4 and insert k1,k2, close at t=2 |
48 | | // Open2 at t=3 with ttl=5. Now k1,k2 should be deleted at t>=5 |
49 | | // read_only=true opens in the usual read-only mode. Compactions will not be |
50 | | // triggered(neither manual nor automatic), so no expired entries removed |
51 | | // |
52 | | // CONSTRAINTS: |
53 | | // Not specifying/passing or non-positive TTL behaves like TTL = infinity |
54 | | // |
55 | | // !!!WARNING!!!: |
56 | | // Calling DB::Open directly to re-open a db created by this API will get |
57 | | // corrupt values(timestamp suffixed) and no ttl effect will be there |
58 | | // during the second Open, so use this API consistently to open the db |
59 | | // Be careful when passing ttl with a small positive value because the |
60 | | // whole database may be deleted in a small amount of time |
61 | | |
62 | | class DBWithTTL : public StackableDB { |
63 | | public: |
64 | | virtual Status CreateColumnFamilyWithTtl( |
65 | | const ColumnFamilyOptions& options, const std::string& column_family_name, |
66 | | ColumnFamilyHandle** handle, int ttl) = 0; |
67 | | |
68 | | static Status Open(const Options& options, const std::string& dbname, |
69 | | DBWithTTL** dbptr, int32_t ttl = 0, |
70 | | bool read_only = false); |
71 | | |
72 | | static Status Open(const DBOptions& db_options, const std::string& dbname, |
73 | | const std::vector<ColumnFamilyDescriptor>& column_families, |
74 | | std::vector<ColumnFamilyHandle*>* handles, |
75 | | DBWithTTL** dbptr, std::vector<int32_t> ttls, |
76 | | bool read_only = false); |
77 | | |
78 | | protected: |
79 | 37 | explicit DBWithTTL(DB* db) : StackableDB(db) {} |
80 | | }; |
81 | | |
82 | | } // namespace rocksdb |
83 | | #endif // ROCKSDB_LITE |