mongoc_collection_count_with_opts - Man Page

WARNING:

Deprecated since version 1.11.0: This function is deprecated and should not be used in new code. Use mongoc_collection_count_documents() or mongoc_collection_estimated_document_count() instead.

mongoc_collection_count_documents() has similar performance to calling mongoc_collection_count() with a non-NULL query, and is guaranteed to retrieve an accurate collection count. See migrating from deprecated count functions for details.

mongoc_collection_estimated_document_count() has the same performance as calling mongoc_collection_count() with a NULL query, but is not guaranteed to retrieve an accurate collection count.

Synopsis

int64_t
mongoc_collection_count_with_opts (mongoc_collection_t *collection,
                                   mongoc_query_flags_t flags,
                                   const bson_t *query,
                                   int64_t skip,
                                   int64_t limit,
                                   const bson_t *opts,
                                   const mongoc_read_prefs_t *read_prefs,
                                   bson_error_t *error)
 BSON_GNUC_DEPRECATED_FOR (mongoc_collection_count_documents or
                           mongoc_collection_estimated_document_count);

Parameters

opts may be NULL or a BSON document with additional command options:

Description

This function shall execute a count query on the underlying 'collection'. The bson 'query' is not validated, simply passed along as appropriate to the server.  As such, compatibility and errors should be validated in the appropriate server documentation.

The mongoc_read_concern_t specified on the mongoc_collection_t will be used, if any. If read_prefs is NULL, the collection's read preferences are used.

In addition to the standard functionality available from mongoc_collection_count, this function allows the user to add arbitrary extra keys to the count.  This pass through enables features such as hinting for counts.

For more information, see the query reference at the MongoDB website.

This function is considered a retryable read operation. Upon a transient error (a network error, errors due to replica set failover, etc.) the operation is safely retried once. If retryreads is false in the URI (see mongoc_uri_t) the retry behavior does not apply.

Errors

Errors are propagated via the error parameter.

Returns

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

Examples

Basic Counting

#include <bson/bson.h>
#include <mongoc/mongoc.h>
#include <stdio.h>

static void
print_query_count (mongoc_collection_t *collection, bson_t *query)
{
   bson_error_t error;
   int64_t count;
   bson_t opts;

   bson_init (&opts);
   BSON_APPEND_UTF8 (&opts, "hint", "_id_");

   count = mongoc_collection_count_with_opts (
      collection, MONGOC_QUERY_NONE, query, 0, 0, &opts, NULL, &error);

   bson_destroy (&opts);

   if (count < 0) {
      fprintf (stderr, "Count failed: %s\n", error.message);
   } else {
      printf ("%" PRId64 " documents counted.\n", count);
   }
}

Counting with Collation

#include <bson/bson.h>
#include <mongoc/mongoc.h>
#include <stdio.h>

static void
print_query_count (mongoc_collection_t *collection, bson_t *query)
{
   bson_t *selector;
   bson_t *opts;
   bson_error_t error;
   int64_t count;

   selector = BCON_NEW ("_id", "{", "$gt", BCON_UTF8 ("one"), "}");

   /* "One" normally sorts before "one"; make "one" come first */
   opts = BCON_NEW ("collation",
                    "{",
                    "locale",
                    BCON_UTF8 ("en_US"),
                    "caseFirst",
                    BCON_UTF8 ("lower"),
                    "}");

   count = mongoc_collection_count_with_opts (
      collection, MONGOC_QUERY_NONE, query, 0, 0, opts, NULL, &error);

   bson_destroy (selector);
   bson_destroy (opts);

   if (count < 0) {
      fprintf (stderr, "Count failed: %s\n", error.message);
   } else {
      printf ("%" PRId64 " documents counted.\n", count);
   }
}

Author

MongoDB, Inc

Info

Mar 06, 2024 1.26.1 libmongoc