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7c673cae | 1 | // Copyright (c) 2011-present, Facebook, Inc. All rights reserved. |
11fdf7f2 TL |
2 | // This source code is licensed under both the GPLv2 (found in the |
3 | // COPYING file in the root directory) and Apache 2.0 License | |
4 | // (found in the LICENSE.Apache file in the root directory). | |
7c673cae FG |
5 | |
6 | #pragma once | |
7 | #ifndef ROCKSDB_LITE | |
8 | ||
9 | #include <string> | |
10 | #include <vector> | |
11 | ||
12 | #include "rocksdb/utilities/stackable_db.h" | |
13 | #include "rocksdb/db.h" | |
14 | ||
15 | namespace rocksdb { | |
16 | ||
17 | // Database with TTL support. | |
18 | // | |
19 | // USE-CASES: | |
20 | // This API should be used to open the db when key-values inserted are | |
21 | // meant to be removed from the db in a non-strict 'ttl' amount of time | |
22 | // Therefore, this guarantees that key-values inserted will remain in the | |
23 | // db for >= ttl amount of time and the db will make efforts to remove the | |
24 | // key-values as soon as possible after ttl seconds of their insertion. | |
25 | // | |
26 | // BEHAVIOUR: | |
27 | // TTL is accepted in seconds | |
28 | // (int32_t)Timestamp(creation) is suffixed to values in Put internally | |
29 | // Expired TTL values deleted in compaction only:(Timestamp+ttl<time_now) | |
30 | // Get/Iterator may return expired entries(compaction not run on them yet) | |
31 | // Different TTL may be used during different Opens | |
32 | // Example: Open1 at t=0 with ttl=4 and insert k1,k2, close at t=2 | |
33 | // Open2 at t=3 with ttl=5. Now k1,k2 should be deleted at t>=5 | |
34 | // read_only=true opens in the usual read-only mode. Compactions will not be | |
35 | // triggered(neither manual nor automatic), so no expired entries removed | |
36 | // | |
37 | // CONSTRAINTS: | |
38 | // Not specifying/passing or non-positive TTL behaves like TTL = infinity | |
39 | // | |
40 | // !!!WARNING!!!: | |
41 | // Calling DB::Open directly to re-open a db created by this API will get | |
42 | // corrupt values(timestamp suffixed) and no ttl effect will be there | |
43 | // during the second Open, so use this API consistently to open the db | |
44 | // Be careful when passing ttl with a small positive value because the | |
45 | // whole database may be deleted in a small amount of time | |
46 | ||
47 | class DBWithTTL : public StackableDB { | |
48 | public: | |
49 | virtual Status CreateColumnFamilyWithTtl( | |
50 | const ColumnFamilyOptions& options, const std::string& column_family_name, | |
51 | ColumnFamilyHandle** handle, int ttl) = 0; | |
52 | ||
53 | static Status Open(const Options& options, const std::string& dbname, | |
54 | DBWithTTL** dbptr, int32_t ttl = 0, | |
55 | bool read_only = false); | |
56 | ||
57 | static Status Open(const DBOptions& db_options, const std::string& dbname, | |
58 | const std::vector<ColumnFamilyDescriptor>& column_families, | |
59 | std::vector<ColumnFamilyHandle*>* handles, | |
60 | DBWithTTL** dbptr, std::vector<int32_t> ttls, | |
61 | bool read_only = false); | |
62 | ||
11fdf7f2 TL |
63 | virtual void SetTtl(int32_t ttl) = 0; |
64 | ||
65 | virtual void SetTtl(ColumnFamilyHandle *h, int32_t ttl) = 0; | |
66 | ||
7c673cae FG |
67 | protected: |
68 | explicit DBWithTTL(DB* db) : StackableDB(db) {} | |
69 | }; | |
70 | ||
71 | } // namespace rocksdb | |
72 | #endif // ROCKSDB_LITE |