Diagnostic Commands

buildInfo

For the buildInfo command, the response contains the following fields:

{
  "ok" : <return>,
  "version" : "<version-number>",
  "versionArray" : [
    <number>,
    <number>,
    <number>,
    <number>
  ],
  "dataLake" : {
    "version" : "<version-number>",
    "gitVersion" : "<version-number>",
    "date" : "<timestamp>",
    "mongoSQLVersion" : "<version-number>"
  }
}

collStats

For the collStats command, Atlas Data Federation omits the following fields in the response:

• avgObjSize

• capped

• max

• maxSize

• wiredTiger

• nindexes

• totalIndexSize

• indexSizes

Atlas Data Federation includes the following fields in the response. You can use these fields to verify what partitions are used to populate a collection, understand how recently the stats were computed, and determine if Atlas Data Federation truncated the output document.

<major-version-number>.<minor-version-number>.<patch-version-number>

{
  ...
  "partitionCount": <number of partitions>,
  "avgPartitionSize": <average size of all partitions>,
  "partitions": [
    {
        "format": <file format>,
        "attributes": <filtering attributes>,
        "count": <number of documents in partition>,
        "source": <cloud storage URL>,
        "size": <size, in bytes, of the partition>
      },
    ...
  ],
  "truncated": false,
  "cacheMetadata": {
    computeTime: ISODate("2021-07-25T15:10:33.513Z"),
    automaticRefreshInProgress: false
  },
  ...
}

Atlas Data Federation introduces an optional boolean parameter, sync, to bypass the cache and fetch the most recent storage statistics for a given collection. The following values are valid for the sync parameter:

• true - to bypass the cache and return the most recent storage statistics

• false - to return cached data

If the sync parameter is omitted, defaults to false.

db.runCommand( {collStats: "<string>", sync: true|false} )

To learn more about the parameters supported by this command, see collStats.

connectionStatus

For connectionStatus command, Atlas Data Federation returns information about the current connection, specifically the state of authenticated users and their available roles.

dbStats

For dbStats command, Atlas Data Federation introduces an optional boolean parameter, sync, to bypass the cache and fetch the most recent storage statistics for a given database. The following values are valid for the sync parameter:

• true - to bypass the cache and return the most recent storage statistics

• false - to use the cached data also

If the sync parameter is omitted, defaults to false.

db.runCommand( {dbStats: 1, sync: true|false} )

To learn more about the parameters supported by this command, see dbStats.

Atlas Data Federation command omits the followig fields in the response:

• object

• avgObjSize

• fsUsedSize

• fsTotalSize

The commands adds the following fields in the response. You can use these fields to determine whether the command returned stale data.

explain

The explain command returns information that describes the Data Federation query plan. The explain output differs from MongoDB in that it provides information about the data partitions used to satisfy the query.

The following commands can be explained in Data Federation:

• aggregate()

• count()

• find()

db.runCommand({ "explain": { "aggregate": "user", "verbosity":
"queryPlannerExtended", "pipeline": [ ], "cursor": {} }})

db.users.explain("executionStats").find({"type": "admin"})

1
{
2
  ok: 1,
3
  stats: { size: '66 B', numberOfPartitions: 2 },
4
  truncated: false,
5
  plan: {
6
    kind: 'region',
7
    region: 'aws/us-east-1',
8
    node: {
9
      kind: 'data',
10
      size: '66 B',
11
      numberOfPartitions: 2,
12
      partitionsTruncated: false,
13
      partitions: [
14
        {
15
          source: 'projectID:cluster',
16
          provider: 'atlas',
17
          size: '4 B',
18
          database: 'locations',
19
          collection: 'nyc'
20
        },
21
        {
22
          source: 'dls:projectID',
23
          provider: 'dls:aws',
24
          size: '62 B',
25
          metadataLocation: { provider: 'aws', region: 'us-east-1' },
26
          dataSetName: 'v1$atlas$archive$etc',
27
          optimizationPlan: { kind: 'everything' }
28
        }
29
      ]
30
    }
31
  }
32
}

1
{
2
  ok: 1,
3
  stats: { size: '66 B', numberOfPartitions: 2 },
4
  truncated: false,
5
  plan: {
6
    kind: 'region',
7
    region: 'aws/us-east-1',
8
    node: {
9
      kind: 'data',
10
      size: '66 B',
11
      numberOfPartitions: 2,
12
      partitionsTruncated: false,
13
      partitions: [
14
        {
15
          source:'projectID:cluster',
16
          provider: 'atlas',
17
          size: '4 B',
18
          database: 'locations',
19
          collection: 'nyc'
20
        },
21
        {
22
          source: 'dls:projectID',
23
          provider: 'dls:aws',
24
          size: '62 B',
25
          metadataLocation: { provider: 'aws', region: 'us-east-1' },
26
          dataSetName: 'v1$atlas$archive$etc',
27
          scannedDataSetPartitionsCount: 1,
28
          percentOfTotalPartitions: 100,
29
          optimizationPlan: { kind: 'everything' }
30
        },
31
      ]
32
    }
33
  }
34
}

1
{
2
  ok: 1,
3
  stats: { size: '66 B', numberOfPartitions: 2 },
4
  truncated: false,
5
  plan: {
6
    kind: 'region',
7
    region: 'aws/us-east-1',
8
    node: {
9
      kind: 'data',
10
      size: '66 B',
11
      numberOfPartitions: 2,
12
      partitionsTruncated: false,
13
      partitions: [
14
        {
15
          source: 'projectID:cluster',
16
          provider: 'atlas',
17
          size: '4 B',
18
          database: 'locations',
19
          collection: 'nyc',
20
          explainResults: {
21
            queryPlanner: {
22
              ...
23
              winningPlan: {
24
                ...
25
              },
26
              rejectedPlans: []
27
            },
28
            executionStats: {
29
              ...
30
            },
31
            stages: {
32
                ...
33
            }
34
          }
35
        },
36
        {
37
          source: 'dls:projectID',
38
          provider: 'dls:aws',
39
          size: '62 B',
40
          metadataLocation: { provider: 'aws', region: 'us-east-1' },
41
          dataSetName: 'v1$atlas$archive$etc'
42
        },
43
      ]
44
    }
45
  }
46
}

getLog

For getLog command, Atlas Data Federation returns a successful response, but doesn't includes log data.

getMore

For getMore command, Atlas Data Federation returns subsequent batches of documents currently pointed to by a cursor, when used in conjunction with commands that return a cursor, e.g. find and aggregate.

hostInfo

For hostInfo command, Atlas Data Federation returns only the following subset of fields from the standard MongoDB response:

{
  "ok" : <return>,
  "system" : {
    "currentTime" : ISODate("<timestamp>"),
    "hostname" : "<hostname>",
    "cpuAddrSize" : <number>,
    "memSizeMB" : <number>,
    "numCores" : <number>,
    "cpuArch" : "<identifier>",
  },
  "os" : {
    "type" : "<string>",
    "name" : "<string>",
  },
  "extra" : { }
}

ping

For ping command, Atlas Data Federation tests whether a server is responding to commands.

whatsmyuri

For whatsmyuri command, Atlas Data Federation returns the client IP address.