1MONGOC_SESSION_OPTS_SET_CAUSAL_CONMSOIlNSiGTbOEmCNo_CnSYgE(oS3cS)ION_OPTS_SET_CAUSAL_CONSISTENCY(3)
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SYNOPSIS

6          void
7          mongoc_session_opts_set_causal_consistency (mongoc_session_opt_t *opts,
8                                                      bool causal_consistency);
9
10       Configure  causal consistency in a session. If true (the default), each
11       operation in the session will be causally ordered  after  the  previous
12       read  or  write  operation. Set to false to disable causal consistency.
13       See the MongoDB Manual Entry for Causal Consistency.
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15       Causal consistency and snapshot reads are mutually exclusive.  Attempt‐
16       ing   to   set   both   to   true   will   result   in  an  error.  See
17       mongoc_session_opts_set_snapshot().
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19       Unacknowledged writes are not causally consistent.  If  you  execute  a
20       write  operation with a mongoc_write_concern_t on which you have called
21       mongoc_write_concern_set_w() with a value of 0, the write does not par‐
22       ticipate in causal consistency.
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PARAMETERS

25       • opts: A mongoc_session_opt_t.
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27       • causal_consistency: True or false.
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EXAMPLE

30          mongoc_client_t *client;
31          mongoc_session_opt_t *session_opts;
32          mongoc_client_session_t *client_session;
33          mongoc_collection_t *collection;
34          bson_t insert_opts = BSON_INITIALIZER;
35          bson_t *doc;
36          bson_error_t error;
37          bool r;
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39          client = mongoc_client_new ("mongodb://example/?appname=session-opts-example");
40          mongoc_client_set_error_api (client, 2);
41
42          session_opts = mongoc_session_opts_new ();
43          mongoc_session_opts_set_causal_consistency (session_opts, false);
44          client_session = mongoc_client_start_session (client, session_opts, &error);
45          mongoc_session_opts_destroy (session_opts);
46
47          if (!client_session) {
48             fprintf (stderr, "Failed to start session: %s\n", error.message);
49             abort ();
50          }
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52          collection = mongoc_client_get_collection (client, "test", "collection");
53          doc = BCON_NEW ("_id", BCON_INT32 (1));
54          r = mongoc_client_session_append (client_session, &insert_opts, NULL);
55          if (!r) {
56             fprintf (stderr, "mongoc_client_session_append failed: %s\n", error.message);
57             abort ();
58          }
59
60          r = mongoc_collection_insert_one (
61             collection, doc, &insert_opts, NULL /* reply */, &error);
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63          if (!r) {
64             fprintf (stderr, "Insert failed: %s\n", error.message);
65             abort ();
66          }
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AUTHOR

69       MongoDB, Inc
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72       2017-present, MongoDB, Inc
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771.25.1                           NMoOvNG0O8C,_S2E0S2S3ION_OPTS_SET_CAUSAL_CONSISTENCY(3)
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