Replicaset has two secondary.
Eventual modeBut in use
labix/mgo.v2When connecting to mongo, I found that all read was concentrated on one secondary, and only a small amount would access the other secondary.
// Read preference modes are specific to mgo: Eventual Mode = 0 // Same as Nearest, but may change servers between reads. Monotonic Mode = 1 // Same as SecondaryPreferred before first write. Same as Primary after first write. Strong Mode = 2 // Same as Primary.
1. Check the setting of connect URL;
2. If the read Load Balance is different from the expectation of the parameters you set, you can consider setting Tag to further configure what member to read from.
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