Provided by: libmongoc-doc_1.3.1-1_all 
NAME
mongoc_uri_t - mongoc_uri_t provides an abstraction on top of the MongoDB connection URI format. It
provides standardized parsing as well as convenience methods for extracting useful information such as
replica hosts or authorization information.
SYNOPSIS
typedef struct _mongoc_uri_t mongoc_uri_t;
DESCRIPTION
mongoc_uri_t provides an abstraction on top of the MongoDB connection URI format. It provides
standardized parsing as well as convenience methods for extracting useful information such as replica
hosts or authorization information.
See Connection String URI Reference on the MongoDB website for more information.
FORMAT
mongodb:// <1>
[username:password@] <2>
host1 <3>
[:port1] <4>
[,host2[:port2],...[,hostN[:portN]]] <5>
[/[database] <6>
[?options]] <7>
\[bu]
mongodb is the specifier of the MongoDB protocol.
\[bu]
An optional username and password.
\[bu]
The only required part of the uri. This specifies either a hostname, IP address or UNIX domain socket.
\[bu]
An optional port number. Defaults to :27017.
\[bu]
Extra optional hosts and ports. You would specify multiple hosts, for example, for connections to
replica sets.
\[bu]
The name of the database to authenticate if the connection string includes authentication credentials.
If /database is not specified and the connection string includes credentials, defaults to the 'admin'
database.
\[bu]
Connection specific options.
REPLICA SET EXAMPLE
To describe a connection to a replica set named 'test' with the following mongod hosts:
\[bu]
db1.example.com on port 27017
\[bu]
db2.example.com on port 2500
You would use the connection string that resembles the following.
mongodb://db1.example.com,db2.example.com:2500/?replicaSet=test
CONNECTION OPTIONS
ssl {true|false}, indicating if SSL must be used. (See also mongoc_client_set_ssl_opts and
mongoc_client_pool_set_ssl_opts \&.)
connectTimeoutMS
A timeout in milliseconds to attempt a connection before timing out. This setting applies to
server discovery and monitoring connections as well as to connections for application operations.
The default is 10 seconds.
socketTimeoutMS
The time in milliseconds to attempt to send or receive on a socket before the attempt times out.
The default is 5 minutes.
NOTE
Setting any of the *TimeoutMS options above to 0 will be interpreted as "use the default value"
SERVER DISCOVERY, MONITORING, AND SELECTION OPTIONS
NOTE
Clients in a mongoc_client_pool_t share a topology scanner that runs on a background thread. The
thread wakes every heartbeatFrequencyMS (default 10 seconds) to scan all MongoDB servers in
parallel. Whenever an application operation requires a server that is not known‐‐for example, if
there is no known primary and your application attempts an insert‐‐the thread rescans all servers
every half‐second. In this situation the pooled client waits up to serverSelectionTimeoutMS
(default 30 seconds) for the thread to find a server suitable for the operation, then returns an
error with domain MONGOC_ERROR_SERVER_SELECTION \&.
Technically, the total time an operation may wait while a pooled client scans the topology is
controlled both by serverSelectionTimeoutMS and connectTimeoutMS \&. The longest wait occurs if
the last scan begins just at the end of the selection timeout, and a slow or down server requires
the full connection timeout before the client gives up.
A non‐pooled client is single‐threaded. Every heartbeatFrequencyMS , it blocks the next
application operation while it does a parallel scan. This scan takes as long as needed to check
the slowest server: roughly connectTimeoutMS \&. Therefore the default heartbeatFrequencyMS for
single‐threaded clients is greater than for pooled clients: 60 seconds.
By default, single‐threaded (non‐pooled) clients scan only once when an operation requires a
server that is not known. If you attempt an insert and there is no known primary, the client
checks all servers once trying to find it, then succeeds or returns an error with domain
MONGOC_ERROR_SERVER_SELECTION \&. But if you set serverSelectionTryOnce to "false", the single‐
threaded client loops, checking all servers every half‐second, until serverSelectionTimeoutMS \&.
The total time an operation may wait for a single‐threaded client to scan the topology is
determined by connectTimeoutMS in the try‐once case, or serverSelectionTimeoutMS and
connectTimeoutMS if serverSelectionTryOnce is set "false".
heartbeatFrequencyMS
The interval between server monitoring checks. Defaults to 10 seconds in pooled (multi‐threaded)
mode, 60 seconds in non‐pooled mode (single‐threaded).
serverSelectionTimeoutMS
A timeout in milliseconds to block for server selection before throwing an exception. The default
is 30 seconds.
serverSelectionTryOnce
If "true", the driver scans the topology exactly once after server selection fails, then either
selects a server or returns an error. If it is false, then the driver repeatedly searches for a
suitable server for up to serverSelectionTimeoutMS milliseconds (pausing a half second between
attempts). The default for serverSelectionTryOnce is "false" for pooled clients, otherwise "true".
Pooled clients ignore serverSelectionTryOnce; they signal the thread to rescan the topology every
half‐second until serverSelectionTimeoutMS expires.
socketCheckIntervalMS
Only applies to single threaded clients. If a socket has not been used within this time, its
connection is checked with a quick "isMaster" call before it is used again. Defaults to 5 seconds.
NOTE
Setting any of the *TimeoutMS options above to 0 will be interpreted as "use the default value"
CONNECTION POOL OPTIONS
maxPoolSize
The maximum number of connections in the pool. The default value is 100.
minPoolSize
The minimum number of connections in the connection pool. Default value is 0. These are lazily
created.
maxIdleTimeMS
Not implemented.
waitQueueMultiple
Not implemented.
waitQueueTimeoutMS
Not implemented.
WRITE CONCERN OPTIONS
w
0 The driver will not acknowledge write operations but will pass or handle any network and socket
errors that it receives to the client. If you disable write concern but enable the getLastError
command’s w option, w overrides the w option.
1 Provides basic acknowledgment of write operations. By specifying 1, you require that a standalone
mongod instance, or the primary for replica sets, acknowledge all write operations. For drivers
released after the default write concern change, this is the default write concern setting.
majority
For replica sets, if you specify the special majority value to w option, write operations will
only return successfully after a majority of the configured replica set members have acknowledged
the write operation.
n For replica sets, if you specify a number n greater than 1, operations with this write concern
return only after n members of the set have acknowledged the write. If you set n to a number that
is greater than the number of available set members or members that hold data, MongoDB will wait,
potentially indefinitely, for these members to become available.
tags For replica sets, you can specify a tag set to require that all members of the set that have these
tags configured return confirmation of the write operation.
wtimeoutMS
The time in milliseconds to wait for replication to succeed, as specified in the w option, before
timing out. When wtimeoutMS is 0, write operations will never time out.
journal
Controls whether write operations will wait until the mongod acknowledges the write operations and
commits the data to the on disk journal.
true Enables journal commit acknowledgment write concern. Equivalent to specifying the getLastError
command with the j option enabled.
false Does not require that mongod commit write operations to the journal before acknowledging the write
operation. This is the default option for the journal parameter.
READ CONCERN OPTIONS
readConcernLevel
The level of isolation for read operations. If the level is left unspecified, the server default
will be used. See the readConcern in the MongoDB Manual for details.
READ PREFERENCE OPTIONS
readPreference
Specifies the replica set read preference for this connection. This setting overrides any slaveOk
value. The read preference values are the following:
\[bu]
primary
\[bu]
primaryPreferred
\[bu]
secondary
\[bu]
secondaryPreferred
\[bu]
nearest
readPreferenceTags
Specifies a tag set as a comma‐seperated list of colon‐separted key‐value pairs.
COLOPHON
This page is part of MongoDB C Driver. Please report any bugs at
https://jira.mongodb.org/browse/CDRIVER.
MongoDB C Driver 2016‐01‐18 MONGOC_URI_T(3)