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Type: Bug
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Resolution: Duplicate
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Priority: Major - P3
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None
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Affects Version/s: 3.0.6
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Component/s: WiredTiger
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None
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Linux
On instance with more than 2k databases, a listDatabase take more than 11s :
2015-10-01T15:01:24.173+0000 I COMMAND [conn3164] command admin.$cmd command: listDatabases { listDatabases: 1.0 } keyUpdates:0 writeConflicts:0 numYields:0 reslen:189925 locks:{ Global: { acquireCount: { r: 5908 } }, Database: { acquireCount: { r: 2954 } } } 11609ms
Tested on several instances :
2015-10-01T15:02:41.537+0000 I COMMAND [conn4713] command admin.$cmd command: listDatabases { listDatabases: 1.0 } keyUpdates:0 writeConflicts:0 numYields:0 reslen:213799 locks:{ Global: { acquireCount: { r: 6626 } }, Database: { acquireCount: { r: 3313 } } } 13618ms 2015-10-01T15:03:10.178+0000 I COMMAND [conn3400] command admin.$cmd command: listDatabases { listDatabases: 1.0 } keyUpdates:0 writeConflicts:0 numYields:0 reslen:187243 locks:{ Global: { acquireCount: { r: 5826 } }, Database: { acquireCount: { r: 2913 } } } 10917ms 2015-10-01T15:03:47.616+0000 I COMMAND [conn316099] command admin.$cmd command: listDatabases { listDatabases: 1.0 } keyUpdates:0 writeConflicts:0 numYields:0 reslen:192677 locks:{ Global: { acquireCount: { r: 5996 } }, Database: { acquireCount: { r: 2998 } } } 11979ms
On another instance, running in 2.6 with mmapv1, listing about 8x more databases take less than 1s :
2015-10-01T15:07:56.751+0000 [conn224132] command admin.$cmd command: listDatabases { listDatabases: 1.0 } keyUpdates:0 numYields:0 locks(micros) R:23663 r:128494 reslen:1300875 866ms
Seems related to SERVER-17078
Mongo version : 3.0.6
OS : Linux / Ubuntu 14.04
Storage configuration :
storageEngine = wiredTiger
wiredTigerCollectionBlockCompressor = snappy
wiredTigerCacheSizeGB = 3
- related to
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SERVER-20961 Large amounts of create and drop collections can cause listDatabases to be slow under WiredTiger
- Closed
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SERVER-21066 Investigate listDatabases option to return only dbnames and skip sizes
- Closed
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SERVER-21067 Investigate having the storage size of a given collection/index/database cached within the WT/KV api
- Closed