本教程介绍如何利用MongoDB C 驱动程序批量写入操作功能。批量执行写入操作可减少网络往返次数,从而提高写入吞吐量。
提示
从MongoDB Server版本 8.0 和C驱动程序版本 1.28 开始,您可以使用 mongoc_bulkwrite_t 类型。此类型使用 bulkWrite服务器命令在单个请求中对混合命名空间执行多种写入操作。有关更多信息,请参阅本指南的 bulkWrite 服务器命令 部分。
Bulk Insert
首先,我们需要从 mongoc_collection_t中获取批量操作处理。
mongoc_bulk_operation_t *bulk =    mongoc_collection_create_bulk_operation_with_opts (collection, NULL); 
我们现在可以开始将文档插入到批量操作中。 这些将被缓冲,直到我们执行操作。
每次连续调用mongoc_bulk_operation_insert时,批量操作会将插入合并为单个批处理。这会在可能的情况下创建管道效果。
为了执行批量操作并接收结果,我们调用 mongoc_bulk_operation_execute。
static void bulk1 (mongoc_collection_t *collection) {    mongoc_bulk_operation_t *bulk;    bson_error_t error;    bson_t *doc;    bson_t reply;    char *str;    bool ret;    int i;    bulk = mongoc_collection_create_bulk_operation_with_opts (collection, NULL);    for (i = 0; i < 10000; i++) {       doc = BCON_NEW ("i", BCON_INT32 (i));       mongoc_bulk_operation_insert (bulk, doc);       bson_destroy (doc);    }    ret = mongoc_bulk_operation_execute (bulk, &reply, &error);    str = bson_as_canonical_extended_json (&reply, NULL);    printf ("%s\n", str);    bson_free (str);    if (!ret) {       fprintf (stderr, "Error: %s\n", error.message);    }    bson_destroy (&reply);    mongoc_bulk_operation_destroy (bulk); } int main (void) {    mongoc_client_t *client;    mongoc_collection_t *collection;    const char *uri_string = "mongodb://localhost/?appname=bulk1-example";    mongoc_uri_t *uri;    bson_error_t error;    mongoc_init ();    uri = mongoc_uri_new_with_error (uri_string, &error);    if (!uri) {       fprintf (stderr,                "failed to parse URI: %s\n"                "error message:       %s\n",                uri_string,                error.message);       return EXIT_FAILURE;    }    client = mongoc_client_new_from_uri (uri);    if (!client) {       return EXIT_FAILURE;    }    mongoc_client_set_error_api (client, 2);    collection = mongoc_client_get_collection (client, "test", "test");    bulk1 (collection);    mongoc_uri_destroy (uri);    mongoc_collection_destroy (collection);    mongoc_client_destroy (client);    mongoc_cleanup ();    return EXIT_SUCCESS; } 
示例reply文档:
{"nInserted"   : 10000,  "nMatched"    : 0,  "nModified"   : 0,  "nRemoved"    : 0,  "nUpserted"   : 0,  "writeErrors" : []  "writeConcernErrors" : [] } 
混合批量写入操作
MongoDB C 驱动程序还支持执行混合批量写入操作。 可以使用批量写入操作 API 一起执行一批插入、更新和删除操作。
有序批量写入操作
有序的批量写入操作会按照为串行执行提供的顺序进行批处理并发送到服务器。 reply文档描述了所执行操作的类型和次数。
static void bulk2 (mongoc_collection_t *collection) {    mongoc_bulk_operation_t *bulk;    bson_error_t error;    bson_t *query;    bson_t *doc;    bson_t *opts;    bson_t reply;    char *str;    bool ret;    int i;    bulk = mongoc_collection_create_bulk_operation_with_opts (collection, NULL);    /* Remove everything */    query = bson_new ();    mongoc_bulk_operation_remove (bulk, query);    bson_destroy (query);    /* Add a few documents */    for (i = 1; i < 4; i++) {       doc = BCON_NEW ("_id", BCON_INT32 (i));       mongoc_bulk_operation_insert (bulk, doc);       bson_destroy (doc);    }    /* {_id: 1} => {$set: {foo: "bar"}} */    query = BCON_NEW ("_id", BCON_INT32 (1));    doc = BCON_NEW ("$set", "{", "foo", BCON_UTF8 ("bar"), "}");    mongoc_bulk_operation_update_many_with_opts (bulk, query, doc, NULL, &error);    bson_destroy (query);    bson_destroy (doc);    /* {_id: 4} => {'$inc': {'j': 1}} (upsert) */    opts = BCON_NEW ("upsert", BCON_BOOL (true));    query = BCON_NEW ("_id", BCON_INT32 (4));    doc = BCON_NEW ("$inc", "{", "j", BCON_INT32 (1), "}");    mongoc_bulk_operation_update_many_with_opts (bulk, query, doc, opts, &error);    bson_destroy (query);    bson_destroy (doc);    bson_destroy (opts);    /* replace {j:1} with {j:2} */    query = BCON_NEW ("j", BCON_INT32 (1));    doc = BCON_NEW ("j", BCON_INT32 (2));    mongoc_bulk_operation_replace_one_with_opts (bulk, query, doc, NULL, &error);    bson_destroy (query);    bson_destroy (doc);    ret = mongoc_bulk_operation_execute (bulk, &reply, &error);    str = bson_as_canonical_extended_json (&reply, NULL);    printf ("%s\n", str);    bson_free (str);    if (!ret) {       printf ("Error: %s\n", error.message);    }    bson_destroy (&reply);    mongoc_bulk_operation_destroy (bulk); } int main (void) {    mongoc_client_t *client;    mongoc_collection_t *collection;    const char *uri_string = "mongodb://localhost/?appname=bulk2-example";    mongoc_uri_t *uri;    bson_error_t error;    mongoc_init ();    uri = mongoc_uri_new_with_error (uri_string, &error);    if (!uri) {       fprintf (stderr,                "failed to parse URI: %s\n"                "error message:       %s\n",                uri_string,                error.message);       return EXIT_FAILURE;    }    client = mongoc_client_new_from_uri (uri);    if (!client) {       return EXIT_FAILURE;    }    mongoc_client_set_error_api (client, 2);    collection = mongoc_client_get_collection (client, "test", "test");    bulk2 (collection);    mongoc_uri_destroy (uri);    mongoc_collection_destroy (collection);    mongoc_client_destroy (client);    mongoc_cleanup ();    return EXIT_SUCCESS; } 
示例reply文档:
{ "nInserted"   : 3,   "nMatched"    : 2,   "nModified"   : 2,   "nRemoved"    : 10000,   "nUpserted"   : 1,   "upserted"    : [{"index" : 5, "_id" : 4}],   "writeErrors" : []   "writeConcernErrors" : [] } 
upserted大量中的index字段是更新或更新或插入(upsert)操作基于0的索引;在此示例中,整个批量操作的第六个操作是更新或更新或插入(upsert),因此其索引为5 。
无序批量写入操作
无序批量写入操作会被分批处理,并以任意顺序发送到服务器,而服务器可能会并行执行这些操作。 尝试所有操作后,都会报告出现的任何错误。
在下一个示例中,第一个和第三个操作由于_id的唯一约束而失败。 由于我们正在进行无序执行,因此第二个和第四个操作会成功。
static void bulk3 (mongoc_collection_t *collection) {    bson_t opts = BSON_INITIALIZER;    mongoc_bulk_operation_t *bulk;    bson_error_t error;    bson_t *query;    bson_t *doc;    bson_t reply;    char *str;    bool ret;    /* false indicates unordered */    BSON_APPEND_BOOL (&opts, "ordered", false);    bulk = mongoc_collection_create_bulk_operation_with_opts (collection, &opts);    bson_destroy (&opts);    /* Add a document */    doc = BCON_NEW ("_id", BCON_INT32 (1));    mongoc_bulk_operation_insert (bulk, doc);    bson_destroy (doc);    /* remove {_id: 2} */    query = BCON_NEW ("_id", BCON_INT32 (2));    mongoc_bulk_operation_remove_one (bulk, query);    bson_destroy (query);    /* insert {_id: 3} */    doc = BCON_NEW ("_id", BCON_INT32 (3));    mongoc_bulk_operation_insert (bulk, doc);    bson_destroy (doc);    /* replace {_id:4} {'i': 1} */    query = BCON_NEW ("_id", BCON_INT32 (4));    doc = BCON_NEW ("i", BCON_INT32 (1));    mongoc_bulk_operation_replace_one (bulk, query, doc, false);    bson_destroy (query);    bson_destroy (doc);    ret = mongoc_bulk_operation_execute (bulk, &reply, &error);    str = bson_as_canonical_extended_json (&reply, NULL);    printf ("%s\n", str);    bson_free (str);    if (!ret) {       printf ("Error: %s\n", error.message);    }    bson_destroy (&reply);    mongoc_bulk_operation_destroy (bulk);    bson_destroy (&opts); } int main (void) {    mongoc_client_t *client;    mongoc_collection_t *collection;    const char *uri_string = "mongodb://localhost/?appname=bulk3-example";    mongoc_uri_t *uri;    bson_error_t error;    mongoc_init ();    uri = mongoc_uri_new_with_error (uri_string, &error);    if (!uri) {       fprintf (stderr,                "failed to parse URI: %s\n"                "error message:       %s\n",                uri_string,                error.message);       return EXIT_FAILURE;    }    client = mongoc_client_new_from_uri (uri);    if (!client) {       return EXIT_FAILURE;    }    mongoc_client_set_error_api (client, 2);    collection = mongoc_client_get_collection (client, "test", "test");    bulk3 (collection);    mongoc_uri_destroy (uri);    mongoc_collection_destroy (collection);    mongoc_client_destroy (client);    mongoc_cleanup ();    return EXIT_SUCCESS; } 
示例reply文档:
{ "nInserted"    : 0,   "nMatched"     : 1,   "nModified"    : 1,   "nRemoved"     : 1,   "nUpserted"    : 0,   "writeErrors"  : [     { "index"  : 0,       "code"   : 11000,       "errmsg" : "E11000 duplicate key error index: test.test.$_id_ dup key: { : 1 }" },     { "index"  : 2,       "code"   : 11000,       "errmsg" : "E11000 duplicate key error index: test.test.$_id_ dup key: { : 3 }" } ],   "writeConcernErrors" : [] } Error: E11000 duplicate key error index: test.test.$_id_ dup key: { : 1 } 
bson_error_t 域为 MONGOC_ERROR_COMMAND,其代码为 11000。
绕过文档验证的批量操作
此功能仅在使用 MongoDB 3.2及更高版本时可用。
默认,批量操作会根据模式(如果已定义)进行验证。 但在某些情况下,可能需要绕过文档验证。
static void bulk5_fail (mongoc_collection_t *collection) {    mongoc_bulk_operation_t *bulk;    bson_error_t error;    bson_t *doc;    bson_t reply;    char *str;    bool ret;    bulk = mongoc_collection_create_bulk_operation_with_opts (collection, NULL);    /* Two inserts */    doc = BCON_NEW ("_id", BCON_INT32 (31));    mongoc_bulk_operation_insert (bulk, doc);    bson_destroy (doc);    doc = BCON_NEW ("_id", BCON_INT32 (32));    mongoc_bulk_operation_insert (bulk, doc);    bson_destroy (doc);    /* The above documents do not comply to the schema validation rules     * we created previously, so this will result in an error */    ret = mongoc_bulk_operation_execute (bulk, &reply, &error);    str = bson_as_canonical_extended_json (&reply, NULL);    printf ("%s\n", str);    bson_free (str);    if (!ret) {       printf ("Error: %s\n", error.message);    }    bson_destroy (&reply);    mongoc_bulk_operation_destroy (bulk); } static void bulk5_success (mongoc_collection_t *collection) {    mongoc_bulk_operation_t *bulk;    bson_error_t error;    bson_t *doc;    bson_t reply;    char *str;    bool ret;    bulk = mongoc_collection_create_bulk_operation_with_opts (collection, NULL);    /* Allow this document to bypass document validation.     * NOTE: When authentication is enabled, the authenticated user must have     * either the "dbadmin" or "restore" roles to bypass document validation */    mongoc_bulk_operation_set_bypass_document_validation (bulk, true);    /* Two inserts */    doc = BCON_NEW ("_id", BCON_INT32 (31));    mongoc_bulk_operation_insert (bulk, doc);    bson_destroy (doc);    doc = BCON_NEW ("_id", BCON_INT32 (32));    mongoc_bulk_operation_insert (bulk, doc);    bson_destroy (doc);    ret = mongoc_bulk_operation_execute (bulk, &reply, &error);    str = bson_as_canonical_extended_json (&reply, NULL);    printf ("%s\n", str);    bson_free (str);    if (!ret) {       printf ("Error: %s\n", error.message);    }    bson_destroy (&reply);    mongoc_bulk_operation_destroy (bulk); } int main (void) {    bson_t *options;    bson_error_t error;    mongoc_client_t *client;    mongoc_collection_t *collection;    mongoc_database_t *database;    const char *uri_string = "mongodb://localhost/?appname=bulk5-example";    mongoc_uri_t *uri;    mongoc_init ();    uri = mongoc_uri_new_with_error (uri_string, &error);    if (!uri) {       fprintf (stderr,                "failed to parse URI: %s\n"                "error message:       %s\n",                uri_string,                error.message);       return EXIT_FAILURE;    }    client = mongoc_client_new_from_uri (uri);    if (!client) {       return EXIT_FAILURE;    }    mongoc_client_set_error_api (client, 2);    database = mongoc_client_get_database (client, "testasdf");    /* Create schema validator */    options = BCON_NEW ("validator", "{", "number", "{", "$gte", BCON_INT32 (5), "}", "}");    collection = mongoc_database_create_collection (database, "collname", options, &error);    if (collection) {       bulk5_fail (collection);       bulk5_success (collection);       mongoc_collection_destroy (collection);    } else {       fprintf (stderr, "Couldn't create collection: '%s'\n", error.message);    }    bson_free (options);    mongoc_uri_destroy (uri);    mongoc_database_destroy (database);    mongoc_client_destroy (client);    mongoc_cleanup ();    return EXIT_SUCCESS; } 
运行上述示例将导致:
{ "nInserted" : 0,   "nMatched" : 0,   "nModified" : 0,   "nRemoved" : 0,   "nUpserted" : 0,   "writeErrors" : [     { "index" : 0,       "code" : 121,       "errmsg" : "Document failed validation" } ] } Error: Document failed validation { "nInserted" : 2,   "nMatched" : 0,   "nModified" : 0,   "nRemoved" : 0,   "nUpserted" : 0,   "writeErrors" : [] } 
bson_error_t 域为 MONGOC_ERROR_COMMAND。
批量操作写关注
默认情况下,批量操作是使用它们所针对的集合的mongoc_write_concern_t来执行的。可以将自定义写关注(write concern)传递给 mongoc_collection_create_bulk_operation_with_opts 方法。写关注错误(例如wtimeout)将在尝试所有操作后报告,无论执行顺序如何。
static void bulk4 (mongoc_collection_t *collection) {    bson_t opts = BSON_INITIALIZER;    mongoc_write_concern_t *wc;    mongoc_bulk_operation_t *bulk;    bson_error_t error;    bson_t *doc;    bson_t reply;    char *str;    bool ret;    wc = mongoc_write_concern_new ();    mongoc_write_concern_set_w (wc, 4);    mongoc_write_concern_set_wtimeout_int64 (wc, 100); /* milliseconds */    mongoc_write_concern_append (wc, &opts);    bulk = mongoc_collection_create_bulk_operation_with_opts (collection, &opts);    /* Two inserts */    doc = BCON_NEW ("_id", BCON_INT32 (10));    mongoc_bulk_operation_insert (bulk, doc);    bson_destroy (doc);    doc = BCON_NEW ("_id", BCON_INT32 (11));    mongoc_bulk_operation_insert (bulk, doc);    bson_destroy (doc);    ret = mongoc_bulk_operation_execute (bulk, &reply, &error);    str = bson_as_canonical_extended_json (&reply, NULL);    printf ("%s\n", str);    bson_free (str);    if (!ret) {       printf ("Error: %s\n", error.message);    }    bson_destroy (&reply);    mongoc_bulk_operation_destroy (bulk);    mongoc_write_concern_destroy (wc);    bson_destroy (&opts); } int main (void) {    mongoc_client_t *client;    mongoc_collection_t *collection;    const char *uri_string = "mongodb://localhost/?appname=bulk4-example";    mongoc_uri_t *uri;    bson_error_t error;    mongoc_init ();    uri = mongoc_uri_new_with_error (uri_string, &error);    if (!uri) {       fprintf (stderr,                "failed to parse URI: %s\n"                "error message:       %s\n",                uri_string,                error.message);       return EXIT_FAILURE;    }    client = mongoc_client_new_from_uri (uri);    if (!client) {       return EXIT_FAILURE;    }    mongoc_client_set_error_api (client, 2);    collection = mongoc_client_get_collection (client, "test", "test");    bulk4 (collection);    mongoc_uri_destroy (uri);    mongoc_collection_destroy (collection);    mongoc_client_destroy (client);    mongoc_cleanup ();    return EXIT_SUCCESS; } 
reply文档和错误消息示例:
{ "nInserted"    : 2,   "nMatched"     : 0,   "nModified"    : 0,   "nRemoved"     : 0,   "nUpserted"    : 0,   "writeErrors"  : [],   "writeConcernErrors" : [     { "code"   : 64,       "errmsg" : "waiting for replication timed out" } ] } Error: waiting for replication timed out 
如果存在写关注(write concern)错误但没有写入错误,则 bson_error_t 域为 。MONGOC_ERROR_WRITE_CONCERN写入错误表示操作失败,因此它们优先于写关注(write concern)错误,后者仅平均值写关注(write concern)尚未满足。
设置排序规则
此功能仅在使用 MongoDB 3.4及更高版本时可用。
static void bulk_collation (mongoc_collection_t *collection) {    mongoc_bulk_operation_t *bulk;    bson_t *opts;    bson_t *doc;    bson_t *selector;    bson_t *update;    bson_error_t error;    bson_t reply;    char *str;    uint32_t ret;    /* insert {_id: "one"} and {_id: "One"} */    bulk = mongoc_collection_create_bulk_operation_with_opts (collection, NULL);    doc = BCON_NEW ("_id", BCON_UTF8 ("one"));    mongoc_bulk_operation_insert (bulk, doc);    bson_destroy (doc);    doc = BCON_NEW ("_id", BCON_UTF8 ("One"));    mongoc_bulk_operation_insert (bulk, doc);    bson_destroy (doc);    /* "One" normally sorts before "one"; make "one" come first */    opts = BCON_NEW ("collation", "{", "locale", BCON_UTF8 ("en_US"), "caseFirst", BCON_UTF8 ("lower"), "}");    /* set x=1 on the document with _id "One", which now sorts after "one" */    update = BCON_NEW ("$set", "{", "x", BCON_INT64 (1), "}");    selector = BCON_NEW ("_id", "{", "$gt", BCON_UTF8 ("one"), "}");    mongoc_bulk_operation_update_one_with_opts (bulk, selector, update, opts, &error);    ret = mongoc_bulk_operation_execute (bulk, &reply, &error);    str = bson_as_canonical_extended_json (&reply, NULL);    printf ("%s\n", str);    bson_free (str);    if (!ret) {       printf ("Error: %s\n", error.message);    }    bson_destroy (&reply);    bson_destroy (update);    bson_destroy (selector);    bson_destroy (opts);    mongoc_bulk_operation_destroy (bulk); } int main (void) {    mongoc_client_t *client;    mongoc_collection_t *collection;    const char *uri_string = "mongodb://localhost/?appname=bulk-collation";    mongoc_uri_t *uri;    bson_error_t error;    mongoc_init ();    uri = mongoc_uri_new_with_error (uri_string, &error);    if (!uri) {       fprintf (stderr,                "failed to parse URI: %s\n"                "error message:       %s\n",                uri_string,                error.message);       return EXIT_FAILURE;    }    client = mongoc_client_new_from_uri (uri);    if (!client) {       return EXIT_FAILURE;    }    mongoc_client_set_error_api (client, 2);    collection = mongoc_client_get_collection (client, "db", "collection");    bulk_collation (collection);    mongoc_uri_destroy (uri);    mongoc_collection_destroy (collection);    mongoc_client_destroy (client);    mongoc_cleanup ();    return EXIT_SUCCESS; } 
运行上述示例将导致:
{ "nInserted" : 2,    "nMatched" : 1,    "nModified" : 1,    "nRemoved" : 0,    "nUpserted" : 0,    "writeErrors" : [  ] } 
未确认的批量写入
对于未确认的写入,将“w”设置为零。驱动程序使用旧版操作码 OP_INSERT、OP_UPDATE 和 OP_DELETE 发送未确认的写入。
static void bulk6 (mongoc_collection_t *collection) {    bson_t opts = BSON_INITIALIZER;    mongoc_write_concern_t *wc;    mongoc_bulk_operation_t *bulk;    bson_error_t error;    bson_t *doc;    bson_t *selector;    bson_t reply;    char *str;    bool ret;    wc = mongoc_write_concern_new ();    mongoc_write_concern_set_w (wc, 0);    mongoc_write_concern_append (wc, &opts);    bulk = mongoc_collection_create_bulk_operation_with_opts (collection, &opts);    doc = BCON_NEW ("_id", BCON_INT32 (10));    mongoc_bulk_operation_insert (bulk, doc);    bson_destroy (doc);    selector = BCON_NEW ("_id", BCON_INT32 (11));    mongoc_bulk_operation_remove_one (bulk, selector);    bson_destroy (selector);    ret = mongoc_bulk_operation_execute (bulk, &reply, &error);    str = bson_as_canonical_extended_json (&reply, NULL);    printf ("%s\n", str);    bson_free (str);    if (!ret) {       printf ("Error: %s\n", error.message);    }    bson_destroy (&reply);    mongoc_bulk_operation_destroy (bulk);    mongoc_write_concern_destroy (wc);    bson_destroy (&opts); } int main (void) {    mongoc_client_t *client;    mongoc_collection_t *collection;    const char *uri_string = "mongodb://localhost/?appname=bulk6-example";    mongoc_uri_t *uri;    bson_error_t error;    mongoc_init ();    uri = mongoc_uri_new_with_error (uri_string, &error);    if (!uri) {       fprintf (stderr,                "failed to parse URI: %s\n"                "error message:       %s\n",                uri_string,                error.message);       return EXIT_FAILURE;    }    client = mongoc_client_new_from_uri (uri);    if (!client) {       return EXIT_FAILURE;    }    mongoc_client_set_error_api (client, 2);    collection = mongoc_client_get_collection (client, "test", "test");    bulk6 (collection);    mongoc_uri_destroy (uri);    mongoc_collection_destroy (collection);    mongoc_client_destroy (client);    mongoc_cleanup ();    return EXIT_SUCCESS; } 
reply文档为空:
{ } 
bulkWrite 服务器命令
本页前面的示例使用 mongoc_bulk_operation_t 类型执行批量写入操作。mongoc_bulk_operation_t 运行 insert、update 和 delete服务器命令。使用 mongoc_bulk_operation_t 的批量写入操作按类型对操作进行群组,并在单独的命令中发送这些操作。只能为每次批量写入指定一个集合。
或者,您可以使用mongoc_bulkwrite_t 类型执行批量写入,该类型会运行 bulkWrite服务器命令。bulkWrite 命令是在MongoDB Server 8.0 中引入的,它支持对同一有效负载中的多个命名空间进行插入、更新和删除操作。
当连接到MongoDB Server版本8.0或更高版本时,我们建议使用mongoc_bulkwrite_t而不是mongoc_bulk_operation_t ,以减少网络往返。
例子
以下示例演示了如何使用mongoc_bulkwrite_t和mongoc_bulkwrite_execute()将文档插入到两个不同的集合中:
// example-bulkwrite shows use of `mongoc_client_bulkwrite`. int main (int argc, char *argv[]) {    bool ok = false;    mongoc_init ();    bson_error_t error;    mongoc_client_t *client = mongoc_client_new ("mongodb://localhost:27017");    mongoc_bulkwriteopts_t *bwo = mongoc_bulkwriteopts_new ();    mongoc_bulkwriteopts_set_verboseresults (bwo, true);    mongoc_bulkwrite_t *bw = mongoc_client_bulkwrite_new (client);    // Insert a document to `db.coll1`    {       bson_t *doc = BCON_NEW ("foo", "bar");       if (!mongoc_bulkwrite_append_insertone (bw, "db.coll1", doc, NULL, &error)) {          HANDLE_ERROR ("Error appending insert one: %s", error.message);       }       bson_destroy (doc);    }    // Insert a document to `db.coll2`    {       bson_t *doc = BCON_NEW ("foo", "baz");       if (!mongoc_bulkwrite_append_insertone (bw, "db.coll2", doc, NULL, &error)) {          HANDLE_ERROR ("Error appending insert one: %s", error.message);       }       bson_destroy (doc);    }    mongoc_bulkwritereturn_t bwr = mongoc_bulkwrite_execute (bw, bwo);    // Print results.    {       BSON_ASSERT (bwr.res); // Has results. NULL only returned for unacknowledged writes.       printf ("Insert count          : %" PRId64 "\n", mongoc_bulkwriteresult_insertedcount (bwr.res));       const bson_t *ir = mongoc_bulkwriteresult_insertresults (bwr.res);       BSON_ASSERT (ir); // Has verbose results. NULL only returned if verbose results not requested.       char *ir_str = bson_as_relaxed_extended_json (ir, NULL);       printf ("Insert results        : %s\n", ir_str);       bson_free (ir_str);    }    // Print all error information. To observe: try setting the `_id` fields to cause a duplicate key error.    if (bwr.exc) {       const char *msg = "(none)";       if (mongoc_bulkwriteexception_error (bwr.exc, &error)) {          msg = error.message;       }       const bson_t *we = mongoc_bulkwriteexception_writeerrors (bwr.exc);       char *we_str = bson_as_relaxed_extended_json (we, NULL);       const bson_t *wce = mongoc_bulkwriteexception_writeconcernerrors (bwr.exc);       char *wce_str = bson_as_relaxed_extended_json (wce, NULL);       const bson_t *er = mongoc_bulkwriteexception_errorreply (bwr.exc);       char *er_str = bson_as_relaxed_extended_json (er, NULL);       printf ("Top-level error       : %s\n", msg);       printf ("Write errors          : %s\n", we_str);       printf ("Write concern errors  : %s\n", wce_str);       printf ("Error reply           : %s\n", er_str);       bson_free (er_str);       bson_free (wce_str);       bson_free (we_str);    }    mongoc_bulkwriteresult_destroy (bwr.res);    mongoc_bulkwriteexception_destroy (bwr.exc);    mongoc_bulkwrite_destroy (bw);    ok = true; fail:    mongoc_client_destroy (client);    mongoc_bulkwriteopts_destroy (bwo);    mongoc_cleanup ();    return ok ? EXIT_SUCCESS : EXIT_FAILURE; } 
深入阅读
有关批量写入操作的更多信息,请参阅以下批量API规范: