Release Notes

The release notes section describes the Amazon DocumentDB (with MongoDB compatibility) features, improvements, and bug fixes by release date. With the launch of MongoDB 4.0 compatibility on November 11, 2020, the release notes will include updates for both the Amazon DocumentDB 3.6 and 4.0 engine versions.

You can determine the current Amazon DocumentDB engine version by running the following command:


1. db.runCommand({getEngineVersion: 1})

If your cluster is not on the latest version of the engine, it is likely that you have pending maintenance available that will upgrade your engine. For more information, see Maintaining Amazon DocumentDB.

January 15, 2021

New Features

See all the new features in this blog post.

Amazon DocumentDB 4.0 (Engine Version 2.0.722)

  • None

Amazon DocumentDB 3.6 (Engine Version 1.0.206295)

  • Ability to use an index with the $lookup aggregation stage
  • find() queries with projections can be served direction from an index (covered query)
  • Ability to use hint() with the findAndModify
  • Performance optimizations for $addToSet operator
  • Improvements to reduce overall index sizes
  • New aggregation operators: $ifNull, $replaceRoot, $setIsSubset, $setInstersection, $setUnion, and $setEquals
  • Users can also end their own cursors without requiring the KillCursor role

November 9, 2020

New Features

See all the new features in this blog post.

Amazon DocumentDB 4.0 (Engine Version 2.0.722)

  • MongoDB 4.0 compatibility
  • ACID transactions
  • Support for cluster(client.watch() or mongo.watch()) and the database level (db.watch()) change streams
  • Ability to start or resume a change streams using startAtOperationTime
  • Extend your change stream retention period to 7 days (previously 24 hours)
  • AWS DMS target for Amazon DocumentDB 4.0
  • CloudWatch metrics: TransactionsOpen, TransactionsOpenMax, TransactionsAborted, TransactionsStarted, and TransactionsCommitted
  • New fields for transactions in currentOp, ServerStatus, and profiler.
  • Ability to use an index with the $lookup aggregation stage
  • find() queries with projections can be served direction from an index (covered query)
  • Ability to use hint() with the findAndModify
  • Performance optimizations for $addToSet operator
  • Improvements to reduce overall index sizes.
  • New aggregation operators: $ifNull, $replaceRoot, $setIsSubset, $setInstersection, $setUnion, and $setEquals
  • With the ListCollection and ListDatabase commands, you can now optionally use the authorizedCollections and authorizedDatabases parameters to allow users to list the collections and databases that they have permission to access without requiring the listCollections and listDatabase roles, respectively
  • Users can also end their own cursors without requiring the KillCursor role
  • Comparing numeric types of subdocuments is now consistent with comparing numeric types of first-level documents. The behavior in Amazon DocumentDB 4.0 is now compatible with MongoDB.

Amazon DocumentDB 3.6 (Engine Version 1.0.206295)

  • None

Bug Fixes and Other Changes

Amazon DocumentDB 4.0 (Engine Version 2.0.722)

  • $setOnInsert no longer allow updates when using the positional operator $. The behavior in Amazon DocumentDB 4.0 is now compatible with MongoDB.
  • Fixed issue with $createCollection and set autoIndexId
  • Projection for nested documents
  • Changed default setting for working memory to scale with instance memory size
  • Garbage collection improvements
  • Lookup with empty key in path, behavior difference with mongo
  • Fixed dateToString bug in timezone behavior
  • Fixed $push (aggregation) to respect sort order
  • Fixed bug in $currentOp with aggregate
  • Fixed issue with readPreference on secondary
  • Fixed issue with validating $createIndex is the same database as the command was issued
  • Fixed inconsistent behavior for minKey, maxKey lookup fails
  • Fixed issue with $size operator not working with composite array
  • Fixed issue with the negation of $in with regex
  • Fixed issue with $distinct command run against a view
  • Fixed issue with aggregations and find commands sorting missing fields differently
  • Fixed $eq to regular expression not checking type
  • Fixed $currentDate bug in timestamp ordinal position behavior
  • Fixed millisecond granularity for $currentDate

Amazon DocumentDB 3.6 (Engine Version 1.0.206295)

  • None

October 30, 2020

New Features

See all the new features in this blog post.

Amazon DocumentDB 3.6 (Engine Version 1.0.206295)

  • Added the ability to open a change stream cursor at the cluster level (client.watch() or mongo.watch()) and the database (db.watch())
  • Ability to increase the change stream retention period to 7 days (previously 24 hours)

Bug Fixes and Other Changes

Amazon DocumentDB 3.6 (Engine Version 1.0.206295)

  • Various general case performance improvements
  • A targeted security improvement
  • Fixed an issue with skip sort on second field of a compound index
  • Enable regular index for equality on single field of a multi-key index (not compound)
  • Fixed authentication race condition
  • Fixed issue that caused an infrequent garbage collection crash
  • RBAC security improvement
  • Added databaseConnectionsMax metric
  • Performance improvements for certain workloads on r5.24xlarge instances

September 22, 2020

New Features

See all the new features in this blog post.

Amazon DocumentDB 3.6 (Engine Version 1.0.206295)

  • $out aggregation stage
  • Increased the maximum number of connections and cursor per instance by as much as 10x

Bug Fixes and Other Changes

Amazon DocumentDB 3.6 (Engine Version 1.0.206295)

  • None

July 10, 2020

New Features

See all the new features in this blog post.

Amazon DocumentDB 3.6 (Engine Version 1.0.206295)

  • Cross Region Snapshot Copy

Bug Fixes and Other Changes

Amazon DocumentDB 3.6 (Engine Version 1.0.206295)

  • None

June 30, 2020

New Features

See all the new features in this blog post.

Amazon DocumentDB 3.6 (Engine Version 1.0.206295)

  • T3 medium instances

Bug Fixes and Other Changes

Amazon DocumentDB 3.6 (Engine Version 1.0.206295)

  • Idle memory reclamation for t3 instances
  • Authentication improvements
  • Improved SASL authentication performance
  • Fixed currentOp issue when exceeding maximum possible ops
  • Fixed killOps issue for bulk update and delete
  • Improvements to $sample performance with $match
  • Fixed support for $$ in cond case in redact stage
  • Fixed various recurring crash root causes
  • Improvements to TTL sweeping to reduce IOs and latency
  • Optimized memory utilization for $unwind
  • Fixed collection stats race condition with drop index
  • Fixed race condition during concurrent index build
  • Fixed infrequent crash in hash_search in index