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db.collection.getShardDistribution()![](/docs/v5.3/assets/link.svg)
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Definition![](/docs/v5.3/assets/link.svg)
db.collection.getShardDistribution()
Important
mongosh Method
This is a
mongosh
method. This is not the documentation forNode.js
or other programming language specific driver methods.In most cases,
mongosh
methods work the same way as the legacymongo
shell methods. However, some legacy methods are unavailable inmongosh
.For the legacy
mongo
shell documentation, refer to the documentation for the corresponding MongoDB Server release:For MongoDB API drivers, refer to the language specific MongoDB driver documentation.
Prints the data distribution statistics for a sharded collection.
Tip
Before running the method, use the
flushRouterConfig
command to refresh the cached routing table to avoid returning stale distribution information for the collection. Once refreshed, rundb.collection.getShardDistribution()
for the collection you wish to build the index.For example:
db.adminCommand( { flushRouterConfig: "test.myShardedCollection" } ); db.getSiblingDB("test").myShardedCollection.getShardDistribution();
Tip
See also:
Output![](/docs/v5.3/assets/link.svg)
Sample Output![](/docs/v5.3/assets/link.svg)
The following is a sample output for the distribution of a sharded collection:
Shard shard-a at shard-a/MyMachine.local:30000,MyMachine.local:30001,MyMachine.local:30002 data : 38.14Mb docs : 1000003 chunks : 2 estimated data per chunk : 19.07Mb estimated docs per chunk : 500001 Shard shard-b at shard-b/MyMachine.local:30100,MyMachine.local:30101,MyMachine.local:30102 data : 38.14Mb docs : 999999 chunks : 3 estimated data per chunk : 12.71Mb estimated docs per chunk : 333333 Totals data : 76.29Mb docs : 2000002 chunks : 5 Shard shard-a contains 50% data, 50% docs in cluster, avg obj size on shard : 40b Shard shard-b contains 49.99% data, 49.99% docs in cluster, avg obj size on shard : 40b
Output Fields![](/docs/v5.3/assets/link.svg)
Shard <shard-a> at <host-a> data : <size-a> docs : <count-a> chunks : <number of chunks-a> estimated data per chunk : <size-a>/<number of chunks-a> estimated docs per chunk : <count-a>/<number of chunks-a> Shard <shard-b> at <host-b> data : <size-b> docs : <count-b> chunks : <number of chunks-b> estimated data per chunk : <size-b>/<number of chunks-b> estimated docs per chunk : <count-b>/<number of chunks-b> Totals data : <stats.size> docs : <stats.count> chunks : <calc total chunks> Shard <shard-a> contains <estDataPercent-a>% data, <estDocPercent-a>% docs in cluster, avg obj size on shard : stats.shards[ <shard-a> ].avgObjSize Shard <shard-b> contains <estDataPercent-b>% data, <estDocPercent-b>% docs in cluster, avg obj size on shard : stats.shards[ <shard-b> ].avgObjSize
The output information displays:
<shard-x>
is a string that holds the shard name.<host-x>
is a string that holds the host name(s).<size-x>
is a number that includes the size of the data, including the unit of measure (e.g.b
,Mb
).<count-x>
is a number that reports the number of documents in the shard.<number of chunks-x>
is a number that reports the number of chunks in the shard.<size-x>/<number of chunks-x>
is a calculated value that reflects the estimated data size per chunk for the shard, including the unit of measure (e.g.b
,Mb
).<count-x>/<number of chunks-x>
is a calculated value that reflects the estimated number of documents per chunk for the shard.<stats.size>
is a value that reports the total size of the data in the sharded collection, including the unit of measure.<stats.count>
is a value that reports the total number of documents in the sharded collection.<calc total chunks>
is a calculated number that reports the number of chunks from all shards, for example:<calc total chunks> = <number of chunks-a> + <number of chunks-b> <estDataPercent-x>
is a calculated value that reflects, for each shard, the data size as the percentage of the collection's total data size, for example:<estDataPercent-x> = <size-x>/<stats.size> <estDocPercent-x>
is a calculated value that reflects, for each shard, the number of documents as the percentage of the total number of documents for the collection, for example:<estDocPercent-x> = <count-x>/<stats.count> stats.shards[ <shard-x> ].avgObjSize
is a number that reflects the average object size, including the unit of measure, for the shard.