1MONGOC_READ_CONCERN_T(3) libmongoc MONGOC_READ_CONCERN_T(3)
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6 mongoc_read_concern_t - mongoc_read_concern_t
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8 Read Concern abstraction
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11 New in MongoDB 3.2.
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13 The mongoc_read_concern_t allows clients to choose a level of isolation
14 for their reads. The default, MONGOC_READ_CONCERN_LEVEL_LOCAL, is right
15 for the great majority of applications.
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17 You can specify a read concern on connection objects, database objects,
18 or collection objects.
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20 See readConcern on the MongoDB website for more information.
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22 Read Concern is only sent to MongoDB when it has explicitly been set by
23 mongoc_read_concern_set_level to anything other than NULL.
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26 ┌────────────────────┬─────────────────────┬─────────────────────┐
27 │Macro │ Description │ First MongoDB ver‐ │
28 │ │ │ sion │
29 ├────────────────────┼─────────────────────┼─────────────────────┤
30 │MONGOC_READ_CON‐ │ Level "local", the │ 3.2 │
31 │CERN_LEVEL_LOCAL │ default. │ │
32 ├────────────────────┼─────────────────────┼─────────────────────┤
33 │MONGOC_READ_CON‐ │ Level "majority". │ 3.2 │
34 │CERN_LEVEL_MAJORITY │ │ │
35 ├────────────────────┼─────────────────────┼─────────────────────┤
36 │MONGOC_READ_CON‐ │ Level "lineariz‐ │ 3.4 │
37 │CERN_LEVEL_LIN‐ │ able". │ │
38 │EARIZABLE │ │ │
39 ├────────────────────┼─────────────────────┼─────────────────────┤
40 │MONGOC_READ_CON‐ │ Level "available". │ 3.6 │
41 │CERN_LEVEL_AVAIL‐ │ │ │
42 │ABLE │ │ │
43 ├────────────────────┼─────────────────────┼─────────────────────┤
44 │MONGOC_READ_CON‐ │ Level "snapshot". │ 4.0 │
45 │CERN_LEVEL_SNAPSHOT │ │ │
46 └────────────────────┴─────────────────────┴─────────────────────┘
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48 For the sake of compatibility with future versions of MongoDB, mon‐
49 goc_read_concern_set_level allows any string, not just this list of
50 known read concern levels.
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52 See Read Concern Levels in the MongoDB manual for more information
53 about the individual read concern levels.
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56 MongoDB, Inc
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59 2017-present, MongoDB, Inc
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641.20.0 Nov 18, 2021 MONGOC_READ_CONCERN_T(3)