1MONGOC_CLIENT_POOL_T(3)        MongoDB C Driver        MONGOC_CLIENT_POOL_T(3)
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NAME

6       mongoc_client_pool_t - mongoc_client_pool_t
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8       A connection pool for multi-threaded programs. See connection-pooling.
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SYNOPSIS

11          typedef struct _mongoc_client_pool_t mongoc_client_pool_t
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13       mongoc_client_pool_t  is the basis for multi-threading in the MongoDB C
14       driver. Since mongoc_client_t  structures  are  not  thread-safe,  this
15       structure is used to retrieve a new mongoc_client_t for a given thread.
16       This structure is thread-safe.
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EXAMPLE

19       example-pool.c.INDENT 0.0
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21          /* gcc example-pool.c -o example-pool $(pkg-config --cflags --libs
22           * libmongoc-1.0) */
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24          /* ./example-pool [CONNECTION_STRING] */
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26          #include <mongoc/mongoc.h>
27          #include <pthread.h>
28          #include <stdio.h>
29
30          static pthread_mutex_t mutex;
31          static bool in_shutdown = false;
32
33          static void *
34          worker (void *data)
35          {
36             mongoc_client_pool_t *pool = data;
37             mongoc_client_t *client;
38             bson_t ping = BSON_INITIALIZER;
39             bson_error_t error;
40             bool r;
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42             BSON_APPEND_INT32 (&ping, "ping", 1);
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44             while (true) {
45                client = mongoc_client_pool_pop (pool);
46                /* Do something with client. If you are writing an HTTP server, you
47                 * probably only want to hold onto the client for the portion of the
48                 * request performing database queries.
49                 */
50                r = mongoc_client_command_simple (
51                   client, "admin", &ping, NULL, NULL, &error);
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53                if (!r) {
54                   fprintf (stderr, "%s\n", error.message);
55                }
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57                mongoc_client_pool_push (pool, client);
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59                pthread_mutex_lock (&mutex);
60                if (in_shutdown || !r) {
61                   pthread_mutex_unlock (&mutex);
62                   break;
63                }
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65                pthread_mutex_unlock (&mutex);
66             }
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68             bson_destroy (&ping);
69             return NULL;
70          }
71
72          int
73          main (int argc, char *argv[])
74          {
75             const char *uri_string = "mongodb://127.0.0.1/?appname=pool-example";
76             mongoc_uri_t *uri;
77             bson_error_t error;
78             mongoc_client_pool_t *pool;
79             pthread_t threads[10];
80             unsigned i;
81             void *ret;
82
83             pthread_mutex_init (&mutex, NULL);
84             mongoc_init ();
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86             if (argc > 1) {
87                uri_string = argv[1];
88             }
89
90             uri = mongoc_uri_new_with_error (uri_string, &error);
91             if (!uri) {
92                fprintf (stderr,
93                         "failed to parse URI: %s\n"
94                         "error message:       %s\n",
95                         uri_string,
96                         error.message);
97                return EXIT_FAILURE;
98             }
99
100             pool = mongoc_client_pool_new (uri);
101             mongoc_client_pool_set_error_api (pool, 2);
102
103             for (i = 0; i < 10; i++) {
104                pthread_create (&threads[i], NULL, worker, pool);
105             }
106
107             sleep (10);
108             pthread_mutex_lock (&mutex);
109             in_shutdown = true;
110             pthread_mutex_unlock (&mutex);
111
112             for (i = 0; i < 10; i++) {
113                pthread_join (threads[i], &ret);
114             }
115
116             mongoc_client_pool_destroy (pool);
117             mongoc_uri_destroy (uri);
118
119             mongoc_cleanup ();
120
121             return EXIT_SUCCESS;
122          }
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AUTHOR

126       MongoDB, Inc
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129       2017-present, MongoDB, Inc
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1341.13.1                           Jan 24, 2019          MONGOC_CLIENT_POOL_T(3)
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