Release Notes for MongoDB 5.3

5.3.2 - Jun 23, 2022

Issues fixed:

• SERVER-65821 Deadlock during setFCV when there are prepared transactions that have not persisted commit/abort decision

• SERVER-65429 Balancer defragmentation policy should be cleared on step down

• SERVER-64403 Find queries with SORT_MERGE collation-encode the missing sort attribute

• SERVER-63531 commitQuorum incorrectly includes buildIndexes:false nodes and error message incorrectly says that only voting nodes are eligible

• SERVER-65270 Multi-planned SBE queries involving large documents do not respect the 'sort' option

• All JIRA issues closed in 5.3.2

• 5.3.2 Changelog

5.3.1 - April 6, 2022

The first release available for MongoDB 5.3 is 5.3.1. All mentions of MongoDB 5.3 features and updates are available in version 5.3.1.

For a list of all changes in 5.3.0, see:

• 5.3.0 Changelog

• All JIRA issues closed in 5.3.0

For a list of all changes in 5.3.1, see:

• 5.3.1 Changelog

• All JIRA issues closed in 5.3.1

New Aggregation Stages

MongoDB 5.3 introduces the following aggregation stages:

New Aggregation Operators

MongoDB 5.3 introduces the following aggregation operators:

setWindowFields Stage with Transactions and snapshot Read Concern

Starting in MongoDB 5.3, you can use the $setWindowFields stage with transactions and the "snapshot" read concern.

KMIP Key Activation

Starting in MongoDB 5.3, security.kmip.activateKeys activates all newly created KMIP keys upon creation and then periodically checks that keys are in an active state.

Polling for Active State Keys

Starting in MongoDB 5.3, security.kmip.keyStatePollingSeconds sets the polling interval in seconds at which mongod polls the KMIP server for active keys.

Limit Rate of Splits and Merges

Starting in MongoDB 5.3, you can use the new chunkDefragmentationThrottlingMS parameter to limit the rate of split and merge commands run by the balancer when the chunks in a sharded collection are defragmented.

Monitor Defragmentation Status

Starting in MongoDB 5.3, the balancerCollectionStatus command returns detailed information when run on a namespace going through chunk defragmentation. The output includes the current phase of the defragmentation and how many chunks are left to process.

To see example output, see Ongoing Defragmentation Process.

Time Series Collection Improvements

Starting in MongoDB 5.3, you can use the $geoNear pipeline operator on any field in a time series collection.

Clustered Collections

Starting in MongoDB 5.3, you can create a collection with a clustered index. Collections created with a clustered index are called clustered collections.

To learn about the benefits compared to a normal collection, see Clustered Collections.

serverStatus Output Change

Starting in MongoDB 5.3, serverStatus includes connections.loadBalanced which reports the number of incoming connections received through a load balancer.

getParameter can Report When Parameters can be Set

Starting in MongoDB 5.3, getParameter can report:

• whether a parameter can be set at startup

• whether a parameter can be set during runtime

You can use the getParameter command to report parameter details by passing { showDetails: true }. You can use getParameter to report details on all parameters by passing { showDetails: true, allParameters: true }.

explain Output Can Includes Fields for Disk Usage on inputStage

Starting in MongoDB 5.3, explain output can include the following disk usage metrics for a GROUP explain.executionStats.executionStages.inputStage that uses the slot-based execution query engine:

• spilledBytesApprox, the approximate number of in-memory bytes spilled to disk in the stage

• spilledRecords, the number of produced records spilled to disk in the stage

• usedDisk, whether the stage wrote to disk

For details, see explain.executionStats.executionStages.inputStage.

Specify a Timeout for Step Up and Step Down Operations

Starting in MongoDB 5.3, the fassertOnLockTimeoutForStepUpDown parameter allows a server that receives a request to step up or down to terminate if it is unable to comply within the timeout.

Multiple Arbiters

Starting in MongoDB 5.3, support for multiple arbiters in a replica set is disabled by default. To enable support for multiple arbiters, start each node with the allowMultipleArbiters parameter.