Details
-
Bug
-
Resolution: Done
-
Major - P3
-
None
-
3.6.4
-
None
-
ALL
-
Description
A MongoDB v3.6.4 database on Debian 9.4 with a large sharded collection with two shards and WiredTiger engine hangs when issuing a findOne() or find() command without any parameters. The collection has only the default index on the _id key.
If findOne() or find() is invoked on any of the shards then it works immediately. If it is invoked on a mongos then it hangs.
With db.currentOp() this can be seen after findOne() is invoked:
{
|
"host" : "db1:27017",
|
"desc" : "conn277",
|
"connectionId" : 277,
|
"client" : "10.240.137.10:57294",
|
"appName" : "MongoDB Shell",
|
"clientMetadata" : {
|
"application" : {
|
"name" : "MongoDB Shell"
|
},
|
"driver" : {
|
"name" : "MongoDB Internal Client",
|
"version" : "3.6.4"
|
},
|
"os" : {
|
"type" : "Linux",
|
"name" : "PRETTY_NAME=\"Debian GNU/Linux 9 (stretch)\"",
|
"architecture" : "x86_64",
|
"version" : "Kernel 4.9.0-6-amd64"
|
},
|
"mongos" : {
|
"host" : "m1:27017",
|
"client" : "10.240.0.0:38190",
|
"version" : "3.6.4"
|
}
|
},
|
"active" : true,
|
"currentOpTime" : "2018-04-28T08:13:26.371+0200",
|
"opid" : 2148656,
|
"secs_running" : NumberLong(4),
|
"microsecs_running" : NumberLong(4344989),
|
"op" : "query",
|
"ns" : "somedb.somecol",
|
"command" : {
|
"find" : "somecol",
|
"limit" : NumberLong(1),
|
"shardVersion" : [
|
Timestamp(188696, 1),
|
ObjectId("5ac6b2abbd8bbc9f42f34a39")
|
],
|
"$clusterTime" : {
|
"clusterTime" : Timestamp(1524896001, 1),
|
"signature" : {
|
"hash" : BinData(0,"RuV/v6Qm7H9AvPMVRNH0jkdIwRM="),
|
"keyId" : NumberLong("6540622458888650772")
|
}
|
},
|
"$client" : {
|
"application" : {
|
"name" : "MongoDB Shell"
|
},
|
"driver" : {
|
"name" : "MongoDB Internal Client",
|
"version" : "3.6.4"
|
},
|
"os" : {
|
"type" : "Linux",
|
"name" : "PRETTY_NAME=\"Debian GNU/Linux 9 (stretch)\"",
|
"architecture" : "x86_64",
|
"version" : "Kernel 4.9.0-6-amd64"
|
},
|
"mongos" : {
|
"host" : "m1:27017",
|
"client" : "10.240.0.0:38190",
|
"version" : "3.6.4"
|
}
|
},
|
"$configServerState" : {
|
"opTime" : {
|
"ts" : Timestamp(1524896001, 1),
|
"t" : NumberLong(3)
|
}
|
},
|
"$db" : "feedback"
|
},
|
"planSummary" : "COLLSCAN",
|
"numYields" : 803,
|
"locks" : {
|
"Global" : "r",
|
"Database" : "r",
|
"Collection" : "r"
|
},
|
"waitingForLock" : false,
|
"lockStats" : {
|
"Global" : {
|
"acquireCount" : {
|
"r" : NumberLong(1608)
|
}
|
},
|
"Database" : {
|
"acquireCount" : {
|
"r" : NumberLong(804)
|
}
|
},
|
"Collection" : {
|
"acquireCount" : {
|
"r" : NumberLong(804)
|
}
|
}
|
}
|
},
|