Does mongo c driver has the function of auto re-connection?

[朱金栋 Zhujindong]

I use the mongo c driver to operate the mongodb ,i just wonder if the driver has the function of auto re-connection? 

And if I use a mongodb cluster with three shards ,how can i connect all of the mongos? 

And how can I do to switch to another mongos when i am using one of the mongos to operate the DB?

Help is welcome.

thanks!

[Wan Bachtiar]

I use the mongo c driver to operate the mongodb ,i just wonder if the driver has the function of auto re-connection?

Hi Zhujin,

The C Driver, like all drivers, implement the Server Discovery and Monitoring Spec. In the case of a standalone mongod, the driver is able to reconnect once the server recovered. In a replica set case, the driver will do a rescan and figures out the new primary after a failover.

Also see the following resources related to reconnection and retries :

• Video: MongoDB Drivers and High Availability Deep Dive
• Blog: Server discovery and monitoring next generation MongoDB drivers
• Server Discovery and Monitoring in MongoDB Drivers
• MongoDB C Driver cursor errors
• Previous forum post: MongoDB C Driver retry operations

if I use a mongodb cluster with three shards ,how can i connect all of the mongos?

Generally, in a sharded cluster it is recommended that an application connects to a mongos instead of the shards primary individually. A mongos instance route the reads and writes from application(s) to the shards. An application don’t normally connect to more than one mongos.

See also Sharding Concepts for more information.

Regards,

Wan.

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