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Type:
Bug
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Resolution: Works as Designed
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Priority:
Minor - P4
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None
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Affects Version/s: 3.0.9
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Component/s: Sharding
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Labels:None
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ALL
when I do sh.shardCollection with one collection on many process at a same time. It almost happens.
How to:
➜ ~ cat shardCollection.js
sh.enableSharding("log")
sh.shardCollection("log.log", {db: "hashed"})
sh.shardCollection("log.log2", {db: "hashed"})
sh.shardCollection("log.log3", {db: "hashed"})
sh.shardCollection("log.log4", {db: "hashed"})
sh.shardCollection("log.log5", {db: "hashed"})
sh.shardCollection("log.log6", {db: "hashed"})
➜ ~ cat test_shardColl.sh
mongo --port 27105 shardCollection.js &
mongo --port 27105 shardCollection.js &
mongo --port 27105 shardCollection.js &
mongo --port 27105 shardCollection.js &
mongo --port 27105 shardCollection.js &
mongo --port 27105 shardCollection.js &
mongo --port 27105 shardCollection.js &
mongo --port 27105 shardCollection.js &
mongo --port 27105 shardCollection.js &
mongo --port 27105 shardCollection.js &
mongo --port 27105 shardCollection.js &
mongo --port 27105 shardCollection.js &
mongo --port 27105 shardCollection.js &
mongo --port 27105 shardCollection.js &
mongo --port 27105 shardCollection.js &
then just execute test_shardColl.sh:
bash test_shardColl.sh
when you setLogLevel(5, "sharding") , you can see logs like this:
2017-04-05T18:09:43.889+0800 W COMMAND [conn20] couldn't move chunk ns: log.log5, shard: shard0001:localhost:27102, lastmod: 1|3||000000000000000000000000, min: { db: 1844674407370955160 }, max: { db: 5534023222112865480 } to shard shard0002:localhost:27103 while sharding collection log.log5. Reason: { ok: 0.0, errmsg: "migration already in progress" }
I suppose that something wrong with ShardCollectionCmd::run() on mongo/s/commands_admin.cpp:
if (to == chunk->getShard())
continue;