What is the method of manually selecting the master node of a replication group in the database
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[detailed description of the problem]
How to manually select the master node of a replication group?
[solution]
1. In the replication group, each node can set the voting weight. When the LSN is the same, the node with the largest weight becomes the primary node. Therefore, you can configure weight through the database, and then call the SdbReplicaGroup.reelect () interface to achieve the manual selection of the primary node.
2. The SdbReplicaGroup.reelect () interface will block the write operation and wait for the node LSN to be consistent before the election. If it times out, it will fail and report an error.
3. For example, group1 on v3.0 has nodes sdbserver:11720 (master) and sdbserver:11750 (standby). The main reference steps are as follows:
> var db = new Sdb ()
> db.updateConf ({weight: 20}, {GroupName: "group1", Svcname: "11750"})
> db.snapshot (SDB_SNAP_CONFIGS, {NodeName: "sdbserver1:11720"}, {weight: 1})
{
"weight": 10
}
> db.snapshot (SDB_SNAP_CONFIGS, {NodeName: "sdbserver1:11750"}, {weight: 1})
{
"weight": 20
}
> db.getRG ('group1'). Reelect ()
When you are finished, look at the master node and switch.
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