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Inconsistency Types

MisplacedCollection

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  • Description
  • Format
  • Example

Description

MisplacedCollection

Indicates that an unsharded collection exists on a shard that is not the primary shard.

New in version 7.0.

Format

{
   type: "MisplacedCollection",
   description: "<string>",
   details: {
      namespace: "<string>",
      shard: "<string>",
      localUUID: UUID("<uuid>")
   }
}

MisplacedCollection inconsistency documents contain the following fields:

Field
Type
Description
type
string

Type of inconsistency document. Returns a value of MisplacedCollection for this inconsistency type.

description
string

Describes the nature of the inconsistency found in the metadata.

details
document

Document with additional information on where the inconsistency exists in the database and sharded cluster.

details.namespace
string

Indicates the database and collection where the inconsistency exists.

details.shard
string

The shard where the inconsistency exists.

details.localUUID
UUID
The local UUID of the misplaced collection.

Example

Use the db.adminCommand() method to call the checkMetadataConsistency command:

db.adminCommand( { checkMetadataConsistency: 1 } )

The method returns a cursor with a batch of documents showing the inconsistencies found in the sharding metadata. The example below shows a cursor with a MisplacedCollection inconsistency document:

{
   cursor: {
      id: Long("0"),
      ns: "test.$cmd.aggregate",
      firstBatch: [
         {
            type: "MisplacedCollection",
            description: "Unsharded collection found on shard different from database primary shard",
            details: {
               namespace: "test.authors",
               shard: "shard02",
               localUUID: new UUID("1ad56770-61e2-48e9-83c6-8ecefe73cfc4")
            }
         }
      ],
   },
   ok: 1
}

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