1MONGOC_URI_T(3) libmongoc MONGOC_URI_T(3)
2
6 mongoc_uri_t - mongoc_uri_t
7
9 typedef struct _mongoc_uri_t mongoc_uri_t;
10
12 mongoc_uri_t provides an abstraction on top of the MongoDB connection
13 URI format. It provides standardized parsing as well as convenience
14 methods for extracting useful information such as replica hosts or
15 authorization information.
16 See Connection String URI Reference on the MongoDB website for more
18 information.
19
21 mongodb[+srv]:// <1>
22 [username:password@] <2>
23 host1 <3>
24 [:port1] <4>
25 [,host2[:port2],...[,hostN[:portN]]] <5>
26 [/[database] <6>
27 [?options]] <7>
28 1. "mongodb" is the specifier of the MongoDB protocol. Use "mon‐
30 godb+srv" with a single service name in place of "host1" to specify
31 the initial list of servers with an SRV record.
32 2. An optional username and password.
34 3. The only required part of the uri. This specifies either a host‐
36 name, IPv4 address, IPv6 address enclosed in "[" and "]", or UNIX
37 domain socket.
38 4. An optional port number. Defaults to :27017.
40 5. Extra optional hosts and ports. You would specify multiple hosts,
42 for example, for connections to replica sets.
43 6. The name of the database to authenticate if the connection string
45 includes authentication credentials. If /database is not specified
46 and the connection string includes credentials, defaults to the
47 'admin' database.
48 7. Connection specific options.
50 NOTE:
52 Option names are case-insensitive. Do not repeat the same option
53 (e.g. "mongodb://localhost/db?opt=value1&OPT=value2") since this may
54 have unexpected results.
55 The MongoDB C Driver exposes constants for each supported connection
57 option. These constants make it easier to discover connection options,
58 but their string values can be used as well.
59 For example, the following calls are equal.
61 uri = mongoc_uri_new ("mongodb://localhost/?" MONGOC_URI_APPNAME "=applicationName");
63 uri = mongoc_uri_new ("mongodb://localhost/?appname=applicationName");
64 uri = mongoc_uri_new ("mongodb://localhost/?appName=applicationName");
65
67 To describe a connection to a replica set named 'test' with the follow‐
68 ing mongod hosts:
69 · db1.example.com on port 27017
71 · db2.example.com on port 2500
73 You would use a connection string that resembles the following.
75 mongodb://db1.example.com,db2.example.com:2500/?replicaSet=test
77
79 If you have configured an SRV record with a name like "_mon‐
80 godb._tcp.server.example.com" whose records are a list of one or more
81 MongoDB server hostnames, use a connection string like this:
82 uri = mongoc_uri_new ("mongodb+srv://server.example.com/?replicaSet=rs&appName=applicationName");
84 The driver prefixes the service name with "_mongodb._tcp.", then per‐
86 forms a DNS SRV query to resolve the service name to one or more host‐
87 names. If this query succeeds, the driver performs a DNS TXT query on
88 the service name (without the "_mongodb._tcp" prefix) for additional
89 URI options configured as TXT records.
90 On Unix, the MongoDB C Driver relies on libresolv to look up SRV and
92 TXT records. If libresolv is unavailable, then using a "mongodb+srv"
93 URI will cause an error. If your libresolv lacks res_nsearch then the
94 driver will fall back to res_search, which is not thread-safe.
95
97 If connecting to a hostname that has both IPv4 and IPv6 DNS records,
98 the behavior follows RFC-6555. A connection to the IPv6 address is
99 attempted first. If IPv6 fails, then a connection is attempted to the
100 IPv4 address. If the connection attempt to IPv6 does not complete
101 within 250ms, then IPv4 is tried in parallel. Whichever succeeds con‐
102 nection first cancels the other. The successful DNS result is cached
103 for 10 minutes.
104 As a consequence, attempts to connect to a mongod only listening on
106 IPv4 may be delayed if there are both A (IPv4) and AAAA (IPv6) DNS
107 records associated with the host.
108 To avoid a delay, configure hostnames to match the MongoDB configura‐
110 tion. That is, only create an A record if the mongod is only listening
111 on IPv4.
112
114 ┌────────────────────┬──────────────────┬────────────────────────────────┐
115 │Constant │ Key │ Description │
116 ├────────────────────┼──────────────────┼────────────────────────────────┤
117 │MON‐ │ retryreads │ If "true" and the │
118 │GOC_URI_RETRYREADS │ │ server is a MongoDB │
119 │ │ │ 3.6+ standalone, │
120 │ │ │ replica set, or │
121 │ │ │ sharded cluster, │
122 │ │ │ the driver safely │
123 │ │ │ retries a read that │
124 │ │ │ failed due to a │
125 │ │ │ network error or │
126 │ │ │ replica set │
127 │ │ │ failover. │
128 └────────────────────┴──────────────────┴────────────────────────────────┘
129 │MONGOC_URI_RETRY‐ │ retrywrites │ If "true" and the │
138 │WRITES │ │ server is a MongoDB │
139 │ │ │ 3.6+ replica set or │
140 │ │ │ sharded cluster, │
141 │ │ │ the driver safely │
142 │ │ │ retries a write │
143 │ │ │ that failed due to │
144 │ │ │ a network error or │
145 │ │ │ replica set │
146 │ │ │ failover. Only │
147 │ │ │ inserts, updates of │
148 │ │ │ single documents, │
149 │ │ │ or deletes of sin‐ │
150 │ │ │ gle documents are │
151 │ │ │ retried. │
152 ├────────────────────┼──────────────────┼────────────────────────────────┤
153 │MONGOC_URI_APPNAME │ appname │ The client applica‐ │
154 │ │ │ tion name. This │
155 │ │ │ value is used by │
156 │ │ │ MongoDB when it │
157 │ │ │ logs connection │
158 │ │ │ information and │
159 │ │ │ profile informa‐ │
160 │ │ │ tion, such as slow │
161 │ │ │ queries. │
162 ├────────────────────┼──────────────────┼────────────────────────────────┤
163 │MONGOC_URI_TLS │ tls │ {true|false}, indi‐ │
164 │ │ │ cating if TLS must │
165 │ │ │ be used. (See also │
166 │ │ │ mon‐ │
167 │ │ │ goc_client_set_ssl_opts │
168 │ │ │ and mon‐ │
169 │ │ │ goc_client_pool_set_ssl_opts.) │
170 ├────────────────────┼──────────────────┼────────────────────────────────┤
171 │MONGOC_URI_COMPRES‐ │ compressors │ Comma separated list of com‐ │
172 │SORS │ │ pressors, if any, to use to │
173 │ │ │ compress the wire protocol │
174 │ │ │ messages. Snappy, zlib, and │
175 │ │ │ zstd are optional build time │
176 │ │ │ dependencies, and enable the │
177 │ │ │ "snappy", "zlib", and "zstd" │
178 │ │ │ values respectively. Defaults │
179 │ │ │ to empty (no compressors). │
180 ├────────────────────┼──────────────────┼────────────────────────────────┤
181 │MONGOC_URI_CONNECT‐ │ connecttimeoutms │ This setting applies to new │
182 │TIMEOUTMS │ │ server connections. It is also │
183 │ │ │ used as the socket timeout for │
184 │ │ │ server discovery and monitor‐ │
185 │ │ │ ing operations. The default is │
186 │ │ │ 10,000 ms (10 seconds). │
187 ├────────────────────┼──────────────────┼────────────────────────────────┤
188 │MONGOC_URI_SOCKET‐ │ sockettimeoutms │ The time in milliseconds to │
189 │TIMEOUTMS │ │ attempt to send or receive on │
190 │ │ │ a socket before the attempt │
191 │ │ │ times out. The default is │
192 │ │ │ 300,000 (5 minutes). │
193 ├────────────────────┼──────────────────┼────────────────────────────────┤
194 │MONGOC_URI_REPLI‐ │ replicaset │ The name of the Replica Set │
195 │CASET │ │ that the driver should connect │
196 │ │ │ to. │
197 └────────────────────┴──────────────────┴────────────────────────────────┘
198 │MONGOC_URI_ZLIBCOM‐ │ zlibcompression‐ │ When the MONGOC_URI_COMPRES‐ │
206 │PRESSIONLEVEL │ level │ SORS includes "zlib" this │
207 │ │ │ options configures the zlib │
208 │ │ │ compression level, when the │
209 │ │ │ zlib compressor is used to │
210 │ │ │ compress client data. │
211 └────────────────────┴──────────────────┴────────────────────────────────┘
212 Setting any of the *timeoutMS options above to 0 will be interpreted as
214 "use the default value".
215
217 ┌────────────────────┬────────────────────┬─────────────────────────┐
218 │Constant │ Key │ Description │
219 ├────────────────────┼────────────────────┼─────────────────────────┤
220 │MONGOC_URI_AUTH‐ │ authmechanism │ Specifies the mech‐ │
221 │MECHANISM │ │ anism to use when │
222 │ │ │ authenticating as │
223 │ │ │ the provided user. │
224 │ │ │ See Authentication │
225 │ │ │ for supported val‐ │
226 │ │ │ ues. │
227 ├────────────────────┼────────────────────┼─────────────────────────┤
228 │MONGOC_URI_AUTH‐ │ authmechanismprop‐ │ Certain authentica‐ │
229 │MECHANISMPROPERTIES │ erties │ tion mechanisms │
230 │ │ │ have additional │
231 │ │ │ options that can be │
232 │ │ │ configured. These │
233 │ │ │ options should be │
234 │ │ │ provided as comma │
235 │ │ │ separated │
236 │ │ │ option_key:option_value │
237 │ │ │ pair and provided │
238 │ │ │ as authMechanism‐ │
239 │ │ │ Properties. │
240 ├────────────────────┼────────────────────┼─────────────────────────┤
241 │MONGOC_URI_AUTH‐ │ authsource │ The authSource defines │
242 │SOURCE │ │ the database that │
243 │ │ │ should be used to │
244 │ │ │ authenticate to. It is │
245 │ │ │ unnecessary to provide │
246 │ │ │ this option the data‐ │
247 │ │ │ base name is the same │
248 │ │ │ as the database used in │
249 │ │ │ the URI. │
250 └────────────────────┴────────────────────┴─────────────────────────┘
251 Mechanism Properties
253 ┌────────────────────┬───────────────────┬─────────────────────┐
254 │Constant │ Key │ Description │
255 ├────────────────────┼───────────────────┼─────────────────────┤
256 │MONGOC_URI_CANONI‐ │ canonicalizehost‐ │ Use the canonical │
257 │CALIZEHOSTNAME │ name │ hostname of the │
258 │ │ │ service, rather │
259 │ │ │ than its configured │
260 │ │ │ alias, when authen‐ │
261 │ │ │ ticating with │
262 │ │ │ Cyrus-SASL Ker‐ │
263 │ │ │ beros. │
264 ├────────────────────┼───────────────────┼─────────────────────┤
265 │MONGOC_URI_GSSAPIS‐ │ gssapiservicename │ Use alternative │
266 │ERVICENAME │ │ service name. The │
267 │ │ │ default is mongodb. │
268 └────────────────────┴───────────────────┴─────────────────────┘
269
271 ──────────────────────────────────────────────────────────────────
272 Constant Key Description
273 ──────────────────────────────────────────────────────────────────
274 MONGOC_URI_TLS tls {true|false}, indi‐
275 cating if TLS must
276 be used.
277 ──────────────────────────────────────────────────────────────────
278 MONGOC_URI_TLSCER‐ tlscertificatekey‐ Path to PEM format‐
279 TIFICATEKEYFILE file ted Private Key,
280 with its Public
281 Certificate con‐
282 catenated at the
283 end.
284 ──────────────────────────────────────────────────────────────────
285 MONGOC_URI_TLSCER‐ tlscertificatekey‐ The password, if
286 TIFICATEKEYPASSWORD password any, to use to
287 unlock encrypted
288 Private Key.
289 ──────────────────────────────────────────────────────────────────
290 MON‐ tlscafile One, or a bundle
291 GOC_URI_TLSCAFILE of, Certificate
292 Authorities whom
293 should be consid‐
294 ered to be trusted.
295 ──────────────────────────────────────────────────────────────────
296 MONGOC_URI_TLSAL‐ tlsallowinvalidcer‐ Accept and ignore
297 LOWINVALIDCERTIFI‐ tificates certificate verifi‐
298 CATES cation errors (e.g.
299 untrusted issuer,
300 expired, etc.)
301 ──────────────────────────────────────────────────────────────────
302 MONGOC_URI_TLSAL‐ tlsallowinvalid‐ Ignore hostname
303 LOWINVALIDHOSTNAMES hostnames verification of the
304 certificate (e.g.
305 Man In The Middle,
306 using valid cer‐
307 tificate, but
308 issued for another
309 hostname)
310 ──────────────────────────────────────────────────────────────────
311 MONGOC_URI_TLSINSE‐ tlsinsecure {true|false}, indi‐
312 CURE cating if insecure
313 TLS options should
314 be used. Currently
315 this implies MON‐
316 GOC_URI_TLSALLOWIN‐
317 VALIDCERTIFICATES
318 and MON‐
319 GOC_URI_TLSALLOWIN‐
320 VALIDHOSTNAMES.
321 ──────────────────────────────────────────────────────────────────
322 MONGOC_URI_TLSDIS‐ tlsdisablecertifi‐ {true|false}, indi‐
323 ABLECERTIFICATERE‐ caterevocationcheck cates if revocation
324 VOCATIONCHECK checking (CRL /
325 OCSP) should be
326 disabled.
327 ──────────────────────────────────────────────────────────────────
328 MONGOC_URI_TLSDIS‐ tlsdisableocspend‐ {true|false}, indi‐
329 ABLEOCSPEND‐ pointcheck cates if OCSP
330 POINTCHECK responder endpoints
331 should not be
332 requested when an
333 OCSP response is
334 not stapled.
335 ┌────────────────────┬─────────────────────┬─────────────────────┐
336 │ │ │ │
337 See│ configuring_tls for│details about these o│ptions and about build│ing
338 lib│mongoc with TLS suppo│rt. │ │
339 │ │ │ │
341 The following options have been deprecated and may be removed from
342 future releases of libmongoc.
343 ┌──────────────────────┬──────────────────┬───────────────────┬──────────────────┐
345 │Constant │ Key │ Deprecated For │ Key │
346 ├──────────────────────┼──────────────────┼───────────────────┼──────────────────┤
347 │MONGOC_URI_SSL │ ssl │ MONGOC_URI_TLS │ tls │
348 ├──────────────────────┼──────────────────┼───────────────────┼──────────────────┤
349 │MON‐ │ sslclientcer‐ │ MON‐ │ tlscertifi‐ │
350 │GOC_URI_SSLCLIENTCER‐ │ tificatekeyfile │ GOC_URI_TLSCER‐ │ catekeyfile │
351 │TIFICATEKEYFILE │ │ TIFICATEKEYFILE │ │
352 ├──────────────────────┼──────────────────┼───────────────────┼──────────────────┤
353 │MON‐ │ sslclientcer‐ │ MON‐ │ tlscertifi‐ │
354 │GOC_URI_SSLCLIENTCER‐ │ tificatekeypass‐ │ GOC_URI_TLSCER‐ │ catekeypassword │
355 │TIFICATEKEYPASSWORD │ word │ TIFICATEKEYPASS‐ │ │
356 │ │ │ WORD │ │
357 ├──────────────────────┼──────────────────┼───────────────────┼──────────────────┤
358 │MONGOC_URI_SSLCER‐ │ sslcertifi‐ │ MON‐ │ tlscafile │
359 │TIFICATEAUTHORITYFILE │ cateauthority‐ │ GOC_URI_TLSCAFILE │ │
360 │ │ file │ │ │
361 ├──────────────────────┼──────────────────┼───────────────────┼──────────────────┤
362 │MONGOC_URI_SSLALLOW‐ │ sslallowinvalid‐ │ MONGOC_URI_TLSAL‐ │ tlsallowinvalid‐ │
363 │INVALIDCERTIFICATES │ certificates │ LOWINVALIDCER‐ │ certificates │
364 │ │ │ TIFICATES │ │
365 ├──────────────────────┼──────────────────┼───────────────────┼──────────────────┤
366 │MONGOC_URI_SSLALLOW‐ │ sslallowinvalid‐ │ MONGOC_URI_TLSAL‐ │ tlsallowinvalid‐ │
367 │INVALIDHOSTNAMES │ hostnames │ LOWINVALIDHOST‐ │ hostnames │
368 │ │ │ NAMES │ │
369 └──────────────────────┴──────────────────┴───────────────────┴──────────────────┘
370
372 Clients in a mongoc_client_pool_t share a topology scanner that runs on
373 a background thread. The thread wakes every heartbeatFrequencyMS
374 (default 10 seconds) to scan all MongoDB servers in parallel. Whenever
375 an application operation requires a server that is not known--for exam‐
376 ple, if there is no known primary and your application attempts an
377 insert--the thread rescans all servers every half-second. In this situ‐
378 ation the pooled client waits up to serverSelectionTimeoutMS (default
379 30 seconds) for the thread to find a server suitable for the operation,
380 then returns an error with domain MONGOC_ERROR_SERVER_SELECTION.
381 Technically, the total time an operation may wait while a pooled client
383 scans the topology is controlled both by serverSelectionTimeoutMS and
384 connectTimeoutMS. The longest wait occurs if the last scan begins just
385 at the end of the selection timeout, and a slow or down server requires
386 the full connection timeout before the client gives up.
387 A non-pooled client is single-threaded. Every heartbeatFrequencyMS, it
389 blocks the next application operation while it does a parallel scan.
390 This scan takes as long as needed to check the slowest server: roughly
391 connectTimeoutMS. Therefore the default heartbeatFrequencyMS for sin‐
392 gle-threaded clients is greater than for pooled clients: 60 seconds.
393 By default, single-threaded (non-pooled) clients scan only once when an
395 operation requires a server that is not known. If you attempt an insert
396 and there is no known primary, the client checks all servers once try‐
397 ing to find it, then succeeds or returns an error with domain MON‐
398 GOC_ERROR_SERVER_SELECTION. But if you set serverSelectionTryOnce to
399 "false", the single-threaded client loops, checking all servers every
400 half-second, until serverSelectionTimeoutMS.
401 The total time an operation may wait for a single-threaded client to
403 scan the topology is determined by connectTimeoutMS in the try-once
404 case, or serverSelectionTimeoutMS and connectTimeoutMS if serverSelec‐
405 tionTryOnce is set "false".
406 ┌────────────────────┬─────────────────────┬─────────────────────┐
408 │Constant │ Key │ Description │
409 └────────────────────┴─────────────────────┴─────────────────────┘
410 │MONGOC_URI_HEART‐ │ heartbeatfrequen‐ │ The interval │
414 │BEATFREQUENCYMS │ cyms │ between server mon‐ │
415 │ │ │ itoring checks. │
416 │ │ │ Defaults to │
417 │ │ │ 10,000ms (10 sec‐ │
418 │ │ │ onds) in pooled │
419 │ │ │ (multi-threaded) │
420 │ │ │ mode, 60,000ms (60 │
421 │ │ │ seconds) in │
422 │ │ │ non-pooled mode │
423 │ │ │ (single-threaded). │
424 ├────────────────────┼─────────────────────┼─────────────────────┤
425 │MONGOC_URI_SERVERS‐ │ serverselection‐ │ A timeout in mil‐ │
426 │ELECTIONTIMEOUTMS │ timeoutms │ liseconds to block │
427 │ │ │ for server selec‐ │
428 │ │ │ tion before throw‐ │
429 │ │ │ ing an exception. │
430 │ │ │ The default is │
431 │ │ │ 30,0000ms (30 sec‐ │
432 │ │ │ onds). │
433 ├────────────────────┼─────────────────────┼─────────────────────┤
434 │MONGOC_URI_SERVERS‐ │ serverselectiontry‐ │ If "true", the │
435 │ELECTIONTRYONCE │ once │ driver scans the │
436 │ │ │ topology exactly │
437 │ │ │ once after server │
438 │ │ │ selection fails, │
439 │ │ │ then either selects │
440 │ │ │ a server or returns │
441 │ │ │ an error. If it is │
442 │ │ │ false, then the │
443 │ │ │ driver repeatedly │
444 │ │ │ searches for a │
445 │ │ │ suitable server for │
446 │ │ │ up to serverSelec‐ │
447 │ │ │ tionTimeoutMS mil‐ │
448 │ │ │ liseconds (pausing │
449 │ │ │ a half second │
450 │ │ │ between attempts). │
451 │ │ │ The default for │
452 │ │ │ serverSelectionTry‐ │
453 │ │ │ Once is "false" for │
454 │ │ │ pooled clients, │
455 │ │ │ otherwise "true". │
456 │ │ │ Pooled clients │
457 │ │ │ ignore serverSelec‐ │
458 │ │ │ tionTryOnce; they │
459 │ │ │ signal the thread │
460 │ │ │ to rescan the │
461 │ │ │ topology every │
462 │ │ │ half-second until │
463 │ │ │ serverSelection‐ │
464 │ │ │ TimeoutMS expires. │
465 ├────────────────────┼─────────────────────┼─────────────────────┤
466 │MONGOC_URI_SOCK‐ │ socketcheckinter‐ │ Only applies to │
467 │ETCHECKINTERVALMS │ valms │ single threaded │
468 │ │ │ clients. If a │
469 │ │ │ socket has not been │
470 │ │ │ used within this │
471 │ │ │ time, its connec‐ │
472 │ │ │ tion is checked │
473 │ │ │ with a quick │
474 │ │ │ "isMaster" call │
475 │ │ │ before it is used │
476 │ │ │ again. Defaults to │
477 │ │ │ 5,000ms (5 sec‐ │
478 │ │ │ onds). │
479 └────────────────────┴─────────────────────┴─────────────────────┘
480 │MONGOC_URI_DIRECT‐ │ directconnection │ If "true", the │
484 │CONNECTION │ │ driver connects to │
485 │ │ │ a single server │
486 │ │ │ directly and will │
487 │ │ │ not monitor addi‐ │
488 │ │ │ tional servers. If │
489 │ │ │ "false", the driver │
490 │ │ │ connects based on │
491 │ │ │ the presence and │
492 │ │ │ value of the repli‐ │
493 │ │ │ caSet option. │
494 └────────────────────┴─────────────────────┴─────────────────────┘
495 Setting any of the *TimeoutMS options above to 0 will be interpreted as
497 "use the default value".
498
500 These options govern the behavior of a mongoc_client_pool_t. They are
501 ignored by a non-pooled mongoc_client_t.
502 ┌────────────────────┬────────────────────┬─────────────────────┐
504 │Constant │ Key │ Description │
505 ├────────────────────┼────────────────────┼─────────────────────┤
506 │MONGOC_URI_MAXPOOL‐ │ maxpoolsize │ The maximum number │
507 │SIZE │ │ of clients created │
508 │ │ │ by a mon‐ │
509 │ │ │ goc_client_pool_t │
510 │ │ │ total (both in the │
511 │ │ │ pool and checked │
512 │ │ │ out). The default │
513 │ │ │ value is 100. Once │
514 │ │ │ it is reached, mon‐ │
515 │ │ │ goc_client_pool_pop │
516 │ │ │ blocks until │
517 │ │ │ another thread │
518 │ │ │ pushes a client. │
519 ├────────────────────┼────────────────────┼─────────────────────┤
520 │MONGOC_URI_MINPOOL‐ │ minpoolsize │ Deprecated. This │
521 │SIZE │ │ option's behavior │
522 │ │ │ does not match its │
523 │ │ │ name, and its │
524 │ │ │ actual behavior │
525 │ │ │ will likely hurt │
526 │ │ │ performance. │
527 ├────────────────────┼────────────────────┼─────────────────────┤
528 │MONGOC_URI_MAXIDLE‐ │ maxidletimems │ Not implemented. │
529 │TIMEMS │ │ │
530 ├────────────────────┼────────────────────┼─────────────────────┤
531 │MONGOC_URI_WAIT‐ │ waitqueuemultiple │ Not implemented. │
532 │QUEUEMULTIPLE │ │ │
533 ├────────────────────┼────────────────────┼─────────────────────┤
534 │MONGOC_URI_WAIT‐ │ waitqueuetimeoutms │ The maximum time to │
535 │QUEUETIMEOUTMS │ │ wait for a client │
536 │ │ │ to become available │
537 │ │ │ from the pool. │
538 └────────────────────┴────────────────────┴─────────────────────┘
539
541 ┌───────────────────┬────────────┬─────────────────────┐
542 │Constant │ Key │ Description │
543 └───────────────────┴────────────┴─────────────────────┘
544 MONGOC_URI_W w Determines the
554 write concern
555 (guarantee). Valid
556 values:
557 · 0 = The
559 driver
560 will not
561 acknowl‐
562 edge write
563 operations
564 but will
565 pass or
566 handle any
567 network
568 and socket
569 errors
570 that it
571 receives
572 to the
573 client. If
574 you dis‐
575 able write
576 concern
577 but enable
578 the get‐
579 LastError
580 command’s
581 w option,
582 w over‐
583 rides the
584 w option.
585 · 1 = Pro‐
587 vides
588 basic
589 acknowl‐
590 edgement
591 of write
592 opera‐
593 tions. By
594 specifying
595 1, you
596 require
597 that a
598 standalone
599 mongod
600 instance,
601 or the
602 primary
603 for
604 replica
605 sets,
606 acknowl‐
607 edge all
608 write
609 opera‐
610 tions. For
611 drivers
612 released
613 after the
614 default
615 write con‐
616 cern
617 change,
618 this is
619 the
620 default
621 write con‐
622 cern set‐
623 ting.
624 · majority =
626 For
627 replica
628 sets, if
629 you spec‐
630 ify the
631 special
632 majority
633 value to w
634 option,
635 write
636 operations
637 will only
638 return
639 success‐
640 fully
641 after a
642 majority
643 of the
644 configured
645 replica
646 set mem‐
647 bers have
648 acknowl‐
649 edged the
650 write
651 operation.
652 · n = For
654 replica
655 sets, if
656 you spec‐
657 ify a num‐
658 ber n
659 greater
660 than 1,
661 operations
662 with this
663 write con‐
664 cern
665 return
666 only after
667 n members
668 of the set
669 have
670 acknowl‐
671 edged the
672 write. If
673 you set n
674 to a num‐
675 ber that
676 is greater
677 than the
678 number of
679 available
680 set mem‐
681 bers or
682 members
683 that hold
684 data, Mon‐
685 goDB will
686 wait,
687 poten‐
688 tially
689 indefi‐
690 nitely,
691 for these
692 members to
693 become
694 available.
695 · tags = For
697 replica
698 sets, you
699 can spec‐
700 ify a tag
701 set to
702 require
703 that all
704 members of
705 the set
706 that have
707 these tags
708 configured
709 return
710 confirma‐
711 tion of
712 the write
713 operation.
714 ├───────────────────┼────────────┼─────────────────────┤
715 │MONGOC_URI_WTIME‐ │ wtimeoutms │ The time in mil‐ │
716 │OUTMS │ │ liseconds to wait │
717 │ │ │ for replication to │
718 │ │ │ succeed, as speci‐ │
719 │ │ │ fied in the w │
720 │ │ │ option, before tim‐ │
721 │ │ │ ing out. When │
722 │ │ │ wtimeoutMS is 0, │
723 │ │ │ write operations │
724 │ │ │ will never time │
725 │ │ │ out. │
726 ├───────────────────┼────────────┼─────────────────────┤
727 │MONGOC_URI_JOURNAL │ journal │ Controls whether │
728 │ │ │ write operations │
729 │ │ │ will wait until the │
730 │ │ │ mongod acknowledges │
731 │ │ │ the write opera‐ │
732 │ │ │ tions and commits │
733 │ │ │ the data to the on │
734 │ │ │ disk journal. │
735 │ │ │ │
736 │ │ │ · true = │
737 │ │ │ Enables │
738 │ │ │ journal │
739 │ │ │ commit │
740 │ │ │ acknowl‐ │
741 │ │ │ edgement │
742 │ │ │ write con‐ │
743 │ │ │ cern. │
744 │ │ │ Equivalent │
745 │ │ │ to speci‐ │
746 │ │ │ fying the │
747 │ │ │ getLastEr‐ │
748 │ │ │ ror com‐ │
749 │ │ │ mand with │
750 │ │ │ the j │
751 │ │ │ option │
752 │ │ │ enabled. │
753 │ │ │ │
754 │ │ │ · false = │
755 │ │ │ Does not │
756 │ │ │ require │
757 │ │ │ that mon‐ │
758 │ │ │ god commit │
759 │ │ │ write │
760 │ │ │ operations │
761 │ │ │ to the │
762 │ │ │ journal │
763 │ │ │ before │
764 │ │ │ acknowl‐ │
765 │ │ │ edging the │
766 │ │ │ write │
767 │ │ │ operation. │
768 │ │ │ This is │
769 │ │ │ the │
770 │ │ │ default │
771 │ │ │ option for │
772 │ │ │ the jour‐ │
773 │ │ │ nal param‐ │
774 │ │ │ eter. │
775 └───────────────────┴────────────┴─────────────────────┘
776
778 ┌────────────────────┬──────────────────┬─────────────────────┐
779 │Constant │ Key │ Description │
780 └────────────────────┴──────────────────┴─────────────────────┘
781 │MONGOC_URI_READCON‐ │ readconcernlevel │ The level of isola‐ │
785 │CERNLEVEL │ │ tion for read oper‐ │
786 │ │ │ ations. If the │
787 │ │ │ level is left │
788 │ │ │ unspecified, the │
789 │ │ │ server default will │
790 │ │ │ be used. See │
791 │ │ │ readConcern in the │
792 │ │ │ MongoDB Manual for │
793 │ │ │ details. │
794 └────────────────────┴──────────────────┴─────────────────────┘
795
797 When connected to a replica set, the driver chooses which member to
798 query using the read preference:
799 1. Choose members whose type matches "readPreference".
801 2. From these, if there are any tags sets configured, choose members
803 matching the first tag set. If there are none, fall back to the next
804 tag set and so on, until some members are chosen or the tag sets are
805 exhausted.
806 3. From the chosen servers, distribute queries randomly among the
808 server with the fastest round-trip times. These include the server
809 with the fastest time and any whose round-trip time is no more than
810 "localThresholdMS" slower.
811 ┌─────────────────────┬─────────────────────┬──────────────────────────┐
813 │Constant │ Key │ Description │
814 ├─────────────────────┼─────────────────────┼──────────────────────────┤
815 │MONGOC_URI_READ‐ │ readpreference │ Specifies the │
816 │PREFERENCE │ │ replica set read │
817 │ │ │ preference for this │
818 │ │ │ connection. This │
819 │ │ │ setting overrides │
820 │ │ │ any slaveOk value. │
821 │ │ │ The read preference │
822 │ │ │ values are the fol‐ │
823 │ │ │ lowing: │
824 │ │ │ │
825 │ │ │ · primary │
826 │ │ │ (default) │
827 │ │ │ │
828 │ │ │ · prima‐ │
829 │ │ │ ryPre‐ │
830 │ │ │ ferred │
831 │ │ │ │
832 │ │ │ · secondary │
833 │ │ │ │
834 │ │ │ · sec‐ │
835 │ │ │ ondaryPre‐ │
836 │ │ │ ferred │
837 │ │ │ │
838 │ │ │ · nearest │
839 ├─────────────────────┼─────────────────────┼──────────────────────────┤
840 │MONGOC_URI_READ‐ │ readpreferencetags │ A representation of │
841 │PREFERENCETAGS │ │ a tag set. See also │
842 │ │ │ mon‐ │
843 │ │ │ goc-read-prefs-tag-sets. │
844 └─────────────────────┴─────────────────────┴──────────────────────────┘
845 │MON‐ │ localthresholdms │ How far to distribute │
855 │GOC_URI_LOCALTHRESH‐ │ │ queries, beyond the │
856 │OLDMS │ │ server with the fastest │
857 │ │ │ round-trip time. By │
858 │ │ │ default, only servers │
859 │ │ │ within 15ms of the │
860 │ │ │ fastest round-trip time │
861 │ │ │ receive queries. │
862 ├─────────────────────┼─────────────────────┼──────────────────────────┤
863 │MONGOC_URI_MAXSTALE‐ │ maxstalenessseconds │ The maximum replication │
864 │NESSSECONDS │ │ lag, in wall clock time, │
865 │ │ │ that a secondary can │
866 │ │ │ suffer and still be eli‐ │
867 │ │ │ gible. The smallest │
868 │ │ │ allowed value for │
869 │ │ │ maxStalenessSeconds is │
870 │ │ │ 90 seconds. │
871 └─────────────────────┴─────────────────────┴──────────────────────────┘
872 NOTE:
874 When connecting to more than one mongos, libmongoc's localThresh‐
875 oldMS applies only to the selection of mongos servers. The threshold
876 for selecting among replica set members in shards is controlled by
877 the mongos's localThreshold command line option.
878
880 For historical reasons, the following options are available. They
881 should however not be used.
882 ┌───────────────────┬─────────┬─────────────────────┐
884 │Constant │ Key │ Description │
885 ├───────────────────┼─────────┼─────────────────────┤
886 │MONGOC_URI_SAFE │ safe │ {true|false} Same │
887 │ │ │ as w={1|0} │
888 ├───────────────────┼─────────┼─────────────────────┤
889 │MONGOC_URI_SLAVEOK │ slaveok │ When set, same as │
890 │ │ │ readPreference=sec‐ │
891 │ │ │ ondaryPreferred │
892 └───────────────────┴─────────┴─────────────────────┘
893
895 MongoDB, Inc
896
898 2017-present, MongoDB, Inc
8991.17.4 Feb 04, 2021 MONGOC_URI_T(3)