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Type:
Bug
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Resolution: Done
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Priority:
Major - P3
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None
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Affects Version/s: None
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Component/s: None
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Labels:None
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ALL
Summary
I have a sharded cluster running MongoDB community 4.0.28 and I am trying to upgrade the config servers to 4.2.20.
The config server replica set has 3 nodes running 4.0.28, and I have added 3 new nodes running 4.2.20 for a total of six servers. I have set priority to 1 in just 2 nodes (one 4.0 and one 4.2) to be able to control the promotion process (the rest of the nodes all have prio:0).
When trying to promote the 4.2 server via rs.stepDown(), the process doesn't complete and clients start complaining that they are unable to reach primary.
Looking at db.currentOp() on the 4.2 host that is trying to become primary I see the following operation which seems to be blocking the promotion process:
{
"type" : "op",
"host" : "xxxxx:27019",
"desc" : "rsSync-0",
"active" : true,
"currentOpTime" : "2022-07-11T17:51:11.927+0000",
"effectiveUsers" : [
{
"user" : "__system",
"db" : "local"
}
],
"opid" : 19266327,
"secs_running" : NumberLong(271),
"microsecs_running" : NumberLong(271661567),
"op" : "command",
"ns" : "config.$cmd",
"command" : {
"createIndexes" : "chunks",
"indexes" : [
{
"name" : "ns_1_min_1",
"key" : {
"ns" : 1,
"min" : 1
},
"unique" : true
}
],
"$db" : "config"
},
"numYields" : 0,
"waitingForLatch" : {
"timestamp" : ISODate("2022-07-11T17:46:40.366Z"),
"captureName" : "ReplicationCoordinatorImpl::_mutex"
},
"locks" : {
"ReplicationStateTransition" : "W"
},
"waitingForLock" : false,
"lockStats" : {
"ParallelBatchWriterMode" : {
"acquireCount" : {
"r" : NumberLong(2)
}
},
"ReplicationStateTransition" : {
"acquireCount" : {
"w" : NumberLong(2)
}
},
"Global" : {
"acquireCount" : {
"w" : NumberLong(2)
}
},
"Database" : {
"acquireCount" : {
"w" : NumberLong(2)
}
},
"Collection" : {
"acquireCount" : {
"w" : NumberLong(1)
}
},
"Mutex" : {
"acquireCount" : {
"r" : NumberLong(1)
}
}
},
"waitingForFlowControl" : false,
"flowControlStats" : {
}
},
The config.chunks collection only has 9 chunks so the index creation should be very fast.
Any help would be appreciated