1MONGOC_COLLECTION_ESTIMATED_DOCUMEMNOTlN_iGCbOOmCUo_NnCTgO(oL3cL)ECTION_ESTIMATED_DOCUMENT_COUNT(3)
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SYNOPSIS

6          int64_t
7          mongoc_collection_estimated_document_count (mongoc_collection_t *collection,
8                                                      const bson_t *opts,
9                                                      const mongoc_read_prefs_t *read_prefs,
10                                                      bson_t *reply,
11                                                      bson_error_t *error);
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PARAMETERS

14       • collection: A mongoc_collection_t.
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16       • opts: A bson_t, NULL to ignore.
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18       • read_prefs: A mongoc_read_prefs_t or NULL.
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20       • reply:  A  location  for an uninitialized bson_t to store the command
21         reply, NULL to ignore. If not NULL, reply will be initialized.
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23       • error: An optional location for a bson_error_t or NULL.
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25       opts may be NULL or a BSON document with additional command options:
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27       • readConcern:    Construct    a    mongoc_read_concern_t    and    use
28         mongoc_read_concern_append() to add the read concern to opts. See the
29         example code for mongoc_client_read_command_with_opts(). Read concern
30         requires MongoDB 3.2 or later, otherwise an error is returned.
31
32       • sessionId:    First,   construct   a   mongoc_client_session_t   with
33         mongoc_client_start_session().  You  can  begin  a  transaction  with
34         mongoc_client_session_start_transaction(),    optionally    with    a
35         mongoc_transaction_opt_t that overrides the  options  inherited  from
36         collection, and use mongoc_client_session_append() to add the session
37         to opts. See the example code for mongoc_client_session_t.
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39       • collation: Configure textual comparisons. See Setting  Collation  Or‐
40         der,  and  the  MongoDB Manual entry on Collation. Collation requires
41         MongoDB 3.2 or later, otherwise an error is returned.
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43       • serverId: To target a specific server, include  an  int32  "serverId"
44         field.  Obtain  the id by calling mongoc_client_select_server(), then
45         mongoc_server_description_id() on its return value.
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47       • skip: An int specifying how many documents matching the query  should
48         be skipped before counting.
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50       • limit: An int specifying the maximum number of documents to count.
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52       • comment: A bson_value_t specifying the comment to attach to this com‐
53         mand. The comment will appear in log messages, profiler  output,  and
54         currentOp output. Requires MongoDB 4.4 or later.
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56       For  a  list  of all options, see the MongoDB Manual entry on the count
57       command.
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DESCRIPTION

60       This functions executes a count query on collection. In  contrast  with
61       mongoc_collection_count_documents(),  the count returned is not guaran‐
62       teed to be accurate.
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64       This function is considered a retryable read operation.  Upon  a  tran‐
65       sient error (a network error, errors due to replica set failover, etc.)
66       the operation is safely retried once.  If retryreads is  false  in  the
67       URI (see mongoc_uri_t) the retry behavior does not apply.
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69   Behavior
70       This method is implemented using the count command. Due to an oversight
71       in versions 5.0.0-5.0.8 of MongoDB, the count command was not  included
72       in  version  "1" of the Stable API. Applications using this method with
73       the Stable API are recommended  to  upgrade  their  server  version  to
74       5.0.9+ or disable strict mode (via :symbol:`mongoc_server_api_strict())
75       to avoid encountering errors.
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ERRORS

78       Errors are propagated via the error parameter.
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RETURNS

81       -1 on failure, otherwise the number of documents counted.
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EXAMPLE

84          #include <bson/bson.h>
85          #include <mongoc/mongoc.h>
86          #include <stdio.h>
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88          static void
89          print_count (mongoc_collection_t *collection, bson_t *query)
90          {
91             bson_error_t error;
92             int64_t count;
93             bson_t* opts = BCON_NEW ("skip", BCON_INT64(5));
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95             count = mongoc_collection_estimated_document_count (
96                collection, opts, NULL, NULL, &error);
97             bson_destroy (opts);
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99             if (count < 0) {
100                fprintf (stderr, "Count failed: %s\n", error.message);
101             } else {
102                printf ("%" PRId64 " documents counted.\n", count);
103             }
104          }
105
106       SEE ALSO:
107          mongoc_collection_count_documents()
108          Count: Behavior in the MongoDB Manual
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AUTHOR

112       MongoDB, Inc
113

115       2017-present, MongoDB, Inc
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1201.25.1                           NMoOvNG0O8C,_C2O0L2L3ECTION_ESTIMATED_DOCUMENT_COUNT(3)
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