Azure Cosmos DB for MongoDB (5.0 server version): Supported features and syntax
APPLIES TO:
MongoDB
Azure Cosmos DB is the Microsoft globally distributed multi-model database service. Azure Cosmos DB offers multiple database APIs. You can communicate with Azure Cosmos DB for MongoDB by using any of the open-source MongoDB client drivers. Azure Cosmos DB for MongoDB supports the use of existing client drivers by adhering to the MongoDB wire protocol.
By using Azure Cosmos DB for MongoDB, you can enjoy the benefits of MongoDB that you're used to, with all of the enterprise capabilities that Azure Cosmos DB provides: global distribution, automatic sharding, availability and latency guarantees, encryption at rest, backups, and much more.
Protocol support
The supported operators and any limitations or exceptions are listed in this article. Any client driver that understands these protocols should be able to connect to Azure Cosmos DB for MongoDB. When you create Azure Cosmos DB for MongoDB accounts, the 3.6+ version of accounts has an endpoint in the format *.mongo.cosmos.azure.com. The 3.2 version of accounts has an endpoint in the format *.documents.azure.com.
Note
This article lists only the supported server commands, and excludes client-side wrapper functions. Client-side wrapper functions such as deleteMany() and updateMany() internally use the delete() and update() server commands. Functions that use supported server commands are compatible with Azure Cosmos DB for MongoDB.
Query language support
Azure Cosmos DB for MongoDB provides comprehensive support for MongoDB query language constructs. In the following sections, you can find the detailed list of currently supported operations, operators, stages, commands, and options.
Database commands
Azure Cosmos DB for MongoDB supports the following database commands.
Query and write operation commands
| Command | Supported |
|---|---|
change streams |
Yes |
delete |
Yes |
eval |
No |
find |
Yes |
findAndModify |
Yes |
getLastError |
Yes |
getMore |
Yes |
getPrevError |
No |
insert |
Yes |
parallelCollectionScan |
No |
resetError |
No |
update |
Yes |
Transaction commands
Note
Multi-document transactions are supported only within a single non-sharded collection. Cross-collection and cross-shard multi-document transactions are not yet supported in the API for MongoDB.
| Command | Supported |
|---|---|
abortTransaction |
Yes |
commitTransaction |
Yes |
Authentication commands
| Command | Supported |
|---|---|
authenticate |
Yes |
getnonce |
Yes |
logout |
Yes |
Administration commands
| Command | Supported |
|---|---|
cloneCollectionAsCapped |
No |
collMod |
No |
connectionStatus |
No |
convertToCapped |
No |
copydb |
No |
create |
Yes |
createIndexes |
Yes |
currentOp |
Yes |
drop |
Yes |
dropDatabase |
Yes |
dropIndexes |
Yes |
filemd5 |
Yes |
killCursors |
Yes |
killOp |
No |
listCollections |
Yes |
listDatabases |
Yes |
listIndexes |
Yes |
reIndex |
Yes |
renameCollection |
No |
Diagnostics commands
| Command | Supported |
|---|---|
buildInfo |
Yes |
collStats |
Yes |
connPoolStats |
No |
connectionStatus |
No |
dataSize |
No |
dbHash |
No |
dbStats |
Yes |
explain |
Yes |
features |
No |
hello |
Yes |
hostInfo |
Yes |
listDatabases |
Yes |
listCommands |
No |
profiler |
No |
serverStatus |
No |
top |
No |
whatsmyuri |
Yes |
Aggregation pipeline
Azure Cosmos DB for MongoDB supports the following aggregation commands.
Aggregation commands
| Command | Supported |
|---|---|
aggregate |
Yes |
count |
Yes |
distinct |
Yes |
mapReduce |
No |
Aggregation stages
| Command | Supported |
|---|---|
addFields |
Yes |
bucket |
No |
bucketAuto |
No |
changeStream |
Yes |
collStats |
No |
count |
Yes |
currentOp |
No |
facet |
Yes |
geoNear |
Yes |
graphLookup |
No |
group |
Yes |
indexStats |
No |
limit |
Yes |
listLocalSessions |
No |
listSessions |
No |
lookup |
Partial |
match |
Yes |
merge |
Yes |
out |
Yes |
planCacheStats |
Yes |
project |
Yes |
redact |
Yes |
regexFind |
Yes |
regexFindAll |
Yes |
regexMatch |
Yes |
replaceRoot |
Yes |
replaceWith |
Yes |
sample |
Yes |
set |
Yes |
skip |
Yes |
sort |
Yes |
sortByCount |
Yes |
unset |
Yes |
unwind |
Yes |
Note
The $lookup aggregation does not yet support the uncorrelated subqueries feature that's introduced in server version 3.6. If you attempt to use the $lookup operator with the let and pipeline fields, an error message that indicates that let is not supported appears.
Boolean expressions
| Command | Supported |
|---|---|
and |
Yes |
not |
Yes |
or |
Yes |
Conversion expressions
| Command | Supported |
|---|---|
convert |
Yes |
toBool |
Yes |
toDate |
Yes |
toDecimal |
Yes |
toDouble |
Yes |
toInt |
Yes |
toLong |
Yes |
toObjectId |
Yes |
toString |
Yes |
Set expressions
| Command | Supported |
|---|---|
setEquals |
Yes |
setIntersection |
Yes |
setUnion |
Yes |
setDifference |
Yes |
setIsSubset |
Yes |
anyElementTrue |
Yes |
allElementsTrue |
Yes |
Comparison expressions
Note
The API for MongoDB does not support comparison expressions that have an array literal in the query.
| Command | Supported |
|---|---|
cmp |
Yes |
eq |
Yes |
gt |
Yes |
gte |
Yes |
lt |
Yes |
lte |
Yes |
ne |
Yes |
in |
Yes |
nin |
Yes |
Arithmetic expressions
| Command | Supported |
|---|---|
abs |
Yes |
add |
Yes |
ceil |
Yes |
divide |
Yes |
exp |
Yes |
floor |
Yes |
ln |
Yes |
log |
Yes |
log10 |
Yes |
mod |
Yes |
multiply |
Yes |
pow |
Yes |
round |
Yes |
sqrt |
Yes |
subtract |
Yes |
trunc |
Yes |
Trigonometry expressions
| Command | Supported |
|---|---|
acos |
Yes |
acosh |
Yes |
asin |
Yes |
asinh |
Yes |
atan |
Yes |
atan2 |
Yes |
atanh |
Yes |
cos |
Yes |
cosh |
Yes |
degreesToRadians |
Yes |
radiansToDegrees |
Yes |
sin |
Yes |
sinh |
Yes |
tan |
Yes |
tanh |
Yes |
String expressions
| Command | Supported |
|---|---|
concat |
Yes |
indexOfBytes |
Yes |
indexOfCP |
Yes |
ltrim |
Yes |
rtrim |
Yes |
trim |
Yes |
split |
Yes |
strLenBytes |
Yes |
strLenCP |
Yes |
strcasecmp |
Yes |
substr |
Yes |
substrBytes |
Yes |
substrCP |
Yes |
toLower |
Yes |
toUpper |
Yes |
Text search operator
| Command | Supported |
|---|---|
meta |
No |
Array expressions
| Command | Supported |
|---|---|
arrayElemAt |
Yes |
arrayToObject |
Yes |
concatArrays |
Yes |
filter |
Yes |
indexOfArray |
Yes |
isArray |
Yes |
objectToArray |
Yes |
range |
Yes |
reverseArray |
Yes |
reduce |
Yes |
size |
Yes |
slice |
Yes |
zip |
Yes |
in |
Yes |
Variable operators
| Command | Supported |
|---|---|
map |
Yes |
let |
Yes |
System variables
| Command | Supported |
|---|---|
$$CLUSTERTIME |
Yes |
$$CURRENT |
Yes |
$$DESCEND |
Yes |
$$KEEP |
Yes |
$$NOW |
Yes |
$$PRUNE |
Yes |
$$REMOVE |
Yes |
$$ROOT |
Yes |
Literal operator
| Command | Supported |
|---|---|
literal |
Yes |
Date expressions
| Command | Supported |
|---|---|
dayOfYear |
Yes |
dayOfMonth |
Yes |
dayOfWeek |
Yes |
year |
Yes |
month |
Yes |
week |
Yes |
hour |
Yes |
minute |
Yes |
second |
Yes |
millisecond |
Yes |
dateToString |
Yes |
isoDayOfWeek |
Yes |
isoWeek |
Yes |
dateFromParts |
Yes |
dateToParts |
Yes |
dateFromString |
Yes |
isoWeekYear |
Yes |
Conditional expressions
| Command | Supported |
|---|---|
cond |
Yes |
ifNull |
Yes |
switch |
Yes |
Data type operator
| Command | Supported |
|---|---|
type |
Yes |
Accumulator expressions
| Command | Supported |
|---|---|
sum |
Yes |
avg |
Yes |
first |
Yes |
last |
Yes |
max |
Yes |
min |
Yes |
push |
Yes |
addToSet |
Yes |
stdDevPop |
Yes |
stdDevSamp |
Yes |
Merge operator
| Command | Supported |
|---|---|
mergeObjects |
Yes |
Data types
Azure Cosmos DB for MongoDB supports documents that are encoded in MongoDB BSON format. Versions 4.0 and later (4.0+) enhance the internal usage of this format to improve performance and reduce costs. Documents that are written or updated through an endpoint running 4.0+ benefit from this optimization.
In an upgrade scenario, documents that were written prior to the upgrade to version 4.0+ won't benefit from the enhanced performance until they're updated via a write operation through the 4.0+ endpoint.
16-MB document support raises the size limit for your documents from 2 MB to 16 MB. This limit applies only to collections that are created after this feature is enabled. When this feature is enabled for your database account, it can't be disabled.
To enable 16-MB document support, change the setting on the Features tab for the resource in the Azure portal or programmatically add the EnableMongo16MBDocumentSupport capability.
We recommend that you enable Server Side Retry and avoid using wildcard indexes to ensure that requests in larger documents succeed. Raising your database or collection request units might also help performance.
| Command | Supported |
|---|---|
Double |
Yes |
String |
Yes |
Object |
Yes |
Array |
Yes |
Binary Data |
Yes |
ObjectId |
Yes |
Boolean |
Yes |
Date |
Yes |
Null |
Yes |
32-bit Integer (int) |
Yes |
Timestamp |
Yes |
64-bit Integer (long) |
Yes |
MinKey |
Yes |
MaxKey |
Yes |
Decimal128 |
Yes |
Regular Expression |
Yes |
JavaScript |
Yes |
JavaScript (with scope) |
Yes |
Undefined |
Yes |
Indexes and index properties
Azure Cosmos DB for MongoDB supports the following index commands and index properties.
Indexes
| Command | Supported |
|---|---|
Single Field Index |
Yes |
Compound Index |
Yes |
Multikey Index |
Yes |
Text Index |
No |
2dsphere |
Yes |
2d Index |
No |
Hashed Index |
No |
Index properties
| Command | Supported |
|---|---|
TTL |
Yes |
Unique |
Yes |
Partial |
Supported only for unique indexes |
Case Insensitive |
No |
Sparse |
No |
Background |
Yes |
Operators
Azure Cosmos DB for MongoDB supports the following operators.
Logical operators
| Command | Supported |
|---|---|
or |
Yes |
and |
Yes |
not |
Yes |
nor |
Yes |
Element operators
| Command | Supported |
|---|---|
exists |
Yes |
type |
Yes |
Evaluation query operators
| Command | Supported |
|---|---|
expr |
Yes |
jsonSchema |
No |
mod |
Yes |
regex |
Yes |
text |
No (Not supported. Use $regex instead.) |
where |
No |
In $regex queries, left-anchored expressions allow index search. However, using the i modifier (case-insensitivity) and the m modifier (multiline) causes the collection to scan in all expressions.
When there's a need to include $ or |, it's best to create two (or more) $regex queries.
For example, change the following original query:
find({x:{$regex: /^abc$/})
To this query:
find({x:{$regex: /^abc/, x:{$regex:/^abc$/}})
The first part of the modified query uses the index to restrict the search to documents that begin with ^abc. The second part of the query matches the exact entries. The bar operator (|) acts as an "or" function. The query find({x:{$regex: /^abc |^def/}) matches the documents in which field x has values that begin with abc or def. To use the index, we recommend that you break the query into two different queries that are joined by the $or operator: find( {$or : [{x: $regex: /^abc/}, {$regex: /^def/}] }).
Array operators
| Command | Supported |
|---|---|
all |
Yes |
elemMatch |
Yes |
size |
Yes |
Comment operator
| Command | Supported |
|---|---|
comment |
Yes |
Projection operators
| Command | Supported |
|---|---|
elemMatch |
Yes |
meta |
No |
slice |
Yes |
Update operators
Field update operators
| Command | Supported |
|---|---|
inc |
Yes |
mul |
Yes |
rename |
Yes |
setOnInsert |
Yes |
set |
Yes |
unset |
Yes |
min |
Yes |
max |
Yes |
currentDate |
Yes |
Array update operators
| Command | Supported |
|---|---|
$ |
Yes |
$[] |
Yes |
$[\<identifier\>] |
Yes |
addToSet |
Yes |
pop |
Yes |
pullAll |
Yes |
pull |
Yes |
push |
Yes |
pushAll |
Yes |
Update modifiers
| Command | Supported |
|---|---|
each |
Yes |
slice |
Yes |
sort |
Yes |
position |
Yes |
Bitwise update operator
| Command | Supported |
|---|---|
bit |
Yes |
bitsAllSet |
No |
bitsAnySet |
No |
bitsAllClear |
No |
bitsAnyClear |
No |
Geospatial operators
| Operator | Supported |
|---|---|
$geoWithin |
Yes |
$geoIntersects |
Yes |
$near |
Yes |
$nearSphere |
Yes |
$geometry |
Yes |
$minDistance |
Yes |
$maxDistance |
Yes |
$center |
No |
$centerSphere |
No |
$box |
No |
$polygon |
No |
Sort operations
When you use the findOneAndUpdate operation, sort operations on a single field are supported. Sort operations on multiple fields aren't supported.
Indexing
The API for MongoDB supports various indexes to enable sorting on multiple fields, improve query performance, and enforce uniqueness.
Client-side field-level encryption
Client-level field encryption is a driver feature and is compatible with the API for MongoDB. Explicit encryption, in which the driver explicitly encrypts each field when it's written, is supported. Automatic encryption isn't supported. Explicit decryption and automatic decryption is supported.
The mongocryptd shouldn't be run because it isn't needed to perform any of the supported operations.
GridFS
Azure Cosmos DB supports GridFS through any GridFS-compatible Mongo driver.
Replication
Azure Cosmos DB supports automatic, native replication at the lowest layers. This logic is also extended to achieve low-latency, global replication. Azure Cosmos DB doesn't support manual replication commands.
Retryable writes
The retryable writes feature enables MongoDB drivers to automatically retry certain write operations. The feature results in more stringent requirements for certain operations, which match MongoDB protocol requirements. With this feature enabled, update operations, including deletes, in sharded collections require the shard key to be included in the query filter or update statement.
For example, with a sharded collection that's sharded on the "country" key, to delete all the documents that have the field "city" = "NYC", the application needs to execute the operation for all shard key ("country") values if the retryable writes feature is enabled.
db.coll.deleteMany({"country": "USA", "city": "NYC"})- Successdb.coll.deleteMany({"city": "NYC"})- Fails with error ShardKeyNotFound(61)
Note
Retryable writes does not support bulk unordered writes at this time. If you want to perform bulk writes with retryable writes enabled, perform bulk ordered writes.
To enable the feature, add the EnableMongoRetryableWrites capability to your database account. This feature can also be enabled on the Features tab in the Azure portal.
Sharding
Azure Cosmos DB supports automatic, server-side sharding. It automatically manages shard creation, placement, and balancing. Azure Cosmos DB doesn't support manual sharding commands, which means that you don't have to invoke commands like addShard, balancerStart, and moveChunk. You need to specify the shard key only when you create the containers or query the data.
Sessions
Azure Cosmos DB doesn't yet support server-side sessions commands.
Time to Live
Azure Cosmos DB supports a Time to Live (TTL) that's based on the time stamp of the document. You can enable TTL for a collection in the Azure portal.
Custom TTL
This feature provides the ability to set a custom TTL on any one field in a collection.
On a collection that has TTL enabled on a field:
Acceptable types are the BSON data type and numeric types (integer, long, or double), which will be interpreted as a Unix millisecond time stamp to determine expiration.
If the TTL field is an array, then the smallest element of the array that is of an acceptable type is considered for document expiry.
If the TTL field is missing from a document, the document doesn’t expire.
If the TTL field isn't an acceptable type, the document doesn't expire.
Limitations of a custom TTL
Only one field in a collection can have a TTL set on it.
With a custom TTL field set, the
\_tsfield can't be used for document expiration.You can't use the
\_tsfield in addition.
Configuration
You can enable a custom TTL by updating the EnableTtlOnCustomPath capability for the account. Learn how to configure capabilities.
Set up the TTL
To set up the TTL, run this command: db.coll.createIndex({"YOUR_CUSTOM_TTL_FIELD":1}, {expireAfterSeconds: 10})
Transactions
Multi-document transactions are supported within an unsharded collection. Multi-document transactions aren't supported across collections or in sharded collections. The timeout for transactions is a fixed 5 seconds.
Manage users and roles
Azure Cosmos DB doesn't yet support users and roles. However, Azure Cosmos DB supports Azure role-based access control (Azure RBAC) and read-write and read-only passwords and keys that can be obtained through the Azure portal (on the Connection Strings page).
Write concerns
Some applications rely on a write concern, which specifies the number of responses that are required during a write operation. Due to how Azure Cosmos DB handles replication in the background, all writes are automatically Quorum by default. Any write concern that's specified by the client code is ignored. Learn how to use consistency levels to maximize availability and performance.
Next steps
- Learn how to use Studio 3T with Azure Cosmos DB for MongoDB.
- Learn how to use Robo 3T with Azure Cosmos DB for MongoDB.
- Explore MongoDB samples with Azure Cosmos DB for MongoDB.
- Trying to do capacity planning for a migration to Azure Cosmos DB? You can use information about your existing database cluster for capacity planning.
- If all you know is the number of vCores and servers in your existing database cluster, read about estimating request units by using vCores or vCPUs.
- If you know typical request rates for your current database workload, read about estimating request units by using the Azure Cosmos DB capacity planner.