Navigation
  • Reference >
  • Command Limitations in Free Tier Clusters

Command Limitations in Free Tier Clusters

Atlas M0 Free Tier and M2/M5 shared starter clusters do not support all functionality available to other clusters.

Important

M0 Free Tier and M2/M5 shared starter clusters do not support read or write operations on the admin database.

For complete documentation on M0/M2/M5 limitations, see Atlas M0 (Free Tier), M2, and M5 Limitations.

Commands With Special Behavior

The following commands exhibit special behavior in M0 Free Tier and M2/M5 shared starter clusters:

Command Description
aggregate

The following limitations apply:

  • The maxTimeMs parameter cannot exceed 600 seconds.
  • The allowDiskUsage parameter is ignored.
count

The following limitations apply:

  • The $where operator is not supported.
  • When run against the local database, you can execute count only on the system.replset and oplog.rs collections.
distinct The $where operator is not supported.
find

The following limitations apply:

  • The $where operator is not supported.
  • In the local database, you can run find only on the oplog.rs collection. When querying the oplog.rs collection, if you specify a condition on the ns field, you must specify an equality condition, such as ns: "test.foo". You cannot use $regex or any other operator with the ns field.
getParameter

Can be executed in a Free Tier cluster in only two variations:

  • {getParameter: 1, authSchemaVersion: 1}
  • {getParameter: 1, authenticationMechanisms: 1}
killOp All MongoDB users associated with a Free Tier account can execute the killOp command to terminate operations by all other MongoDB users associated with the same account.
serverStatus
  • The data returned by the following sections is not meaningful:

    • asserts
    • extra_info
    • mem
    • opcountersRepl
  • The following sections are not supported:

    • backgroundFlushing
    • dur
    • encryptionAtRest
    • security
    • advisoryHostFQDNs
    • tcmalloc
    • oplog
    • rangeDeleter
  • The metrics field is replaced with the following:

    "metrics": {
       "connectionPool": {
           "totalCreated": [total-created-number]
       },
    "bytesInWrites": [current-bytes-in-writes-value-since-last-check]
    }
    

Unsupported Commands

The following commands are not supported.

applyOps
appendOplogNote
authenticate
authSchemaUpgrade
checkShardingIndex
cleanupOrphaned
clone
cloneCollection
cloneCollectionAsCapped
compact
connPoolSync
copydb
copydbgetnonce
copydbsaslstart
createRole
createUser
currentOpCtx
dataSize
dbHash
diagLogging
dropAllRolesFromDatabase
dropAllUsersFromDatabase
dropRole
eval
forcerror
fsync
fsyncUnlock
getDiagnosticData
getPrevError
getShardMap
getShardVersion
grantPrivilegesToRole
grantRolesToRole
grantRolesToUser
handshake
invalidateUserCache
lockInfo
logRotate
mapreduce
mapreduce.shardedfinish
parallelCollectionScan
planCacheClear
planCacheClearFilters
planCacheListFilters
planCacheListPlans
planCacheListQueryShapes
planCacheSetFilter
reIndex
revokeRolesFromUser
repairCursor
repairDatabase
replSetDeclareElectionWinner
replSetElect
replSetFreeze
replSetFresh
replSetGetConfig
replSetGetRBID
replSetGetStatus
replSetHeartbeat
replSetInitiate
replSetMaintenance
replSetReconfig
replSetRequestVotes
replSetStepDown
replSetStepUp
replSetSyncFrom
replSetUpdatePosition
resetError
resync
revokePrivilegesFromRole
revokeRolesFromRole
setFeatureCompatibilityVersion
setLogLevel
setParameter
setProfilingLevel
shutdown
updateRole
updateUser
validate
_migrateClone
_recvChunkAbort
_recvChunkCommit
_recvChunkStart
_recvChunkStatus
_transferMods