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Sharding

clearJumboFlag

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  • Definition
  • Compatibility
  • Syntax
  • Access Control
  • Example

Definition

clearJumboFlag

Clears the jumbo flag for a chunk. To use the command, issue the clearJumboFlag command on a mongos instance.

Compatibility

This command is available in deployments hosted in the following environments:

  • MongoDB Atlas: The fully managed service for MongoDB deployments in the cloud

Important

This command is not supported in serverless instances. For more information, see Unsupported Commands.

Syntax

Th command has the following syntax:

db.adminCommand(
   {
     clearJumboFlag: "<database>.<collection>",
     bounds: <array>
   }
)

-OR-

// Cannot use for collections with hashed shard keys
db.adminCommand(
   {
     clearJumboFlag: "<database>.<collection>",
     find: <query>
   }
)

Command Fields

The clearJumboFlag command takes the following fields as arguments:

Field
Type
Description

clearJumboFlag

string

The namespace of the sharded collection with the jumbo chunk(s).

Specify the collection's full namespace, including the database name (i.e. "<database>.<collection>")

bounds

array

The exact bounds of a specific chunk. The array must consist of two documents that specify the lower and upper shard key values of a chunk to move:

[ { <shardKey> : <minValue> },{ <shardKey> : <maxValue> } ]

find

document

A specific shard key and its value contained in the jumbo chunk.

{ <shardKey> : <value> }

Access Control

On systems running with authorization, the user must have the clearJumboFlag privilege actions on the { db: "", collection: "" } resource.

The built-in role clusterManager provides the appropriate privileges.

Example

Clear Jumbo Flag for a Chunk (Range-Based Shard Key)

The sh.status() includes the following sh.status.databases.<collection>.chunk-details for the test.jumbo collection.

... // Content omitted for brevity
test.jumbo
         shard key: { "x" : 1 }
         unique: false
         balancing: true
         chunks:
                  shardA   2
                  shardB   2
         { "x" : { "$minKey" : 1 } } -->> { "x" : 1 } on : shardB Timestamp(3, 0)
         { "x" : 1 } -->> { "x" : 2 } on : shardA Timestamp(6, 1) jumbo
         { "x" : 2 } -->> { "x" : 3 } on : shardA Timestamp(5, 1) jumbo
         { "x" : 3 } -->> { "x" : { "$maxKey" : 1 } } on : shardB Timestamp(6, 0)

The following clearJumboFlag command specifies the bounds of the { "x" : 1 } -->> { "x" : 2 } chunk:

db.adminCommand( {
   clearJumboFlag: "test.jumbo",
   bounds: [{ "x" : 1 }, { "x" : 2 }]
} )

Upon success, the command returns "ok": 1 in its output:

{
   "ok" : 1,
   "operationTime" : Timestamp(1580190080, 5),
   "$clusterTime" : {
      "clusterTime" : Timestamp(1580190080, 5),
      "signature" : {
         "hash" : BinData(0,"0cYT49s72MHUYV1F2WpoEwlyeVs="),
         "keyId" : NumberLong("6786859092951433239")
      }
   }
}

The following clearJumboFlag command specifies the find field to find the chunk that contains the shard key { "x" : 2 } :

db.adminCommand( {
   clearJumboFlag: "test.jumbo",
   find: { "x" : 2 }
} )

Upon success, the command returns "ok": 1 in its output:

{
   "ok" : 1,
   "operationTime" : Timestamp(1580191819, 5),
   "$clusterTime" : {
      "clusterTime" : Timestamp(1580191819, 5),
      "signature" : {
         "hash" : BinData(0,"N6x6drN7HUq5MR5ezUJns1rfeqY="),
         "keyId" : NumberLong("6786859092951433239")
      }
   }
}

To verify the operation, run sh.status() again. The jumbo flag should no longer appear in its output.

... // Content omitted for brevity
test.jumbo
         shard key: { "x" : 1 }
         unique: false
         balancing: true
         chunks:
                  shardA   2
                  shardB   2
         { "x" : { "$minKey" : 1 } } -->> { "x" : 1 } on : shardB Timestamp(3, 0)
         { "x" : 1 } -->> { "x" : 2 } on : shardA Timestamp(7, 0)
         { "x" : 2 } -->> { "x" : 3 } on : shardA Timestamp(8, 0)
         { "x" : 3 } -->> { "x" : { "$maxKey" : 1 } } on : shardB Timestamp(6, 0)

Clear Jumbo Flag for a Chunk (Hashed Shard Key)

The sh.status() includes the following sh.status.databases.<collection>.chunk-details for the test.jumboHashed collection. The collection uses a hashed shard key.

... // Content omitted for brevity
test.jumboHashed
         shard key: { "x" : "hashed" }
         unique: false
         balancing: true
         chunks:
                  shardA   2
                  shardB   2
         { "x" : { "$minKey" : 1 } } -->> { "x" : NumberLong(0) } on : shardA Timestamp(1, 0)
         { "x" : NumberLong(0) } -->> { "x" : NumberLong("848411777775835583") } on : shardA Timestamp(4, 0)
         { "x" : NumberLong("848411777775835583") } -->> { "x" : NumberLong("5902408780260971510") } on : shardB Timestamp(4, 1) jumbo
         { "x" : NumberLong("5902408780260971510") } -->> { "x" : { "$maxKey" : 1 } } on : shardB Timestamp(2, 2)

To clear the jumbo flag for a chunk if the collection uses a hashed shard key, use clearJumboFlag with the bounds field:

db.adminCommand( {
   clearJumboFlag: "test.jumboHashed",
   bounds: [{ "x" : NumberLong("848411777775835583") }, { "x" : NumberLong("5902408780260971510") }]
} )

Upon success, the command returns "ok": 1 in its output:

{
   "ok" : 1,
   "operationTime" : Timestamp(1580194290, 5),
   "$clusterTime" : {
      "clusterTime" : Timestamp(1580194290, 5),
      "signature" : {
         "hash" : BinData(0,"nWCqOYVrab7NEGHWoo2NYENqHR4="),
         "keyId" : NumberLong("6786875525496307742")
      }
   }
}

To verify the operation, run sh.status() again. The jumbo flag should no longer appear in its output.

... // Content omitted for brevity
test.jumboHashed
         shard key: { "x" : "hashed" }
         unique: false
         balancing: true
         chunks:
                  shardA     2
                  shardB     2
         { "x" : { "$minKey" : 1 } } -->> { "x" : NumberLong(0) } on : shardA Timestamp(1, 0)
         { "x" : NumberLong(0) } -->> { "x" : NumberLong("848411777775835583") } on : shardA Timestamp(4, 0)
         { "x" : NumberLong("848411777775835583") } -->> { "x" : NumberLong("5902408780260971510") } on : shardB Timestamp(5, 0)
         { "x" : NumberLong("5902408780260971510") } -->> { "x" : { "$maxKey" : 1 } } on : shardB Timestamp(2, 2)

Tip

See also:

Clear jumbo Flag

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