Merge pull request #192600 from nayakshweta/shwetn_marchreleases

PRMerger10 · web-flow · commit 546a2e080318 · 2022-04-11T08:13:30.000-07:00
Updates recent improvements in unique indexes, TTL indexes and $expr.
diff --git a/articles/cosmos-db/mongodb/feature-support-36.md b/articles/cosmos-db/mongodb/feature-support-36.md
@@ -4,7 +4,7 @@ description: Learn about Azure Cosmos DB's API for MongoDB (3.6 version) support
 ms.service: cosmos-db
 ms.subservice: cosmosdb-mongo
 ms.topic: overview
-ms.date: 03/02/2021
+ms.date: 04/04/2022
 author: gahl-levy
 ms.author: gahllevy
 ---
@@ -377,7 +377,7 @@ Azure Cosmos DB's API for MongoDB supports the following database commands:
 |---------|---------|
 | TTL | Yes |
 | Unique | Yes |
-| Partial | No |
+| Partial | Only supported with unique indexes |
 | Case Insensitive | No |
 | Sparse | No |
 | Background | Yes |
@@ -404,7 +404,7 @@ Azure Cosmos DB's API for MongoDB supports the following database commands:
 
 | Command | Supported |
 |---------|---------|
-| $expr | No |
+| $expr | Yes |
 | $jsonSchema | No |
 | $mod | Yes |
 | $regex | Yes |
diff --git a/articles/cosmos-db/mongodb/feature-support-40.md b/articles/cosmos-db/mongodb/feature-support-40.md
@@ -4,7 +4,7 @@ description: Learn about Azure Cosmos DB's API for MongoDB 4.0 server version su
 ms.service: cosmos-db
 ms.subservice: cosmosdb-mongo
 ms.topic: overview
-ms.date: 08/26/2021
+ms.date: 04/05/2022
 author: gahl-levy
 ms.author: gahllevy
 ---
@@ -399,7 +399,7 @@ In an [upgrade scenario](upgrade-mongodb-version.md), documents written prior to
 |---------|---------|
 | TTL | Yes |
 | Unique | Yes |
-| Partial | No |
+| Partial | Only supported with unique indexes |
 | Case Insensitive | No |
 | Sparse | No |
 | Background | Yes |
@@ -426,7 +426,7 @@ In an [upgrade scenario](upgrade-mongodb-version.md), documents written prior to
 
 | Command | Supported |
 |---------|---------|
-| $expr | No |
+| $expr | Yes |
 | $jsonSchema | No |
 | $mod | Yes |
 | $regex | Yes |
@@ -557,7 +557,7 @@ Azure Cosmos DB does not yet support server-side sessions commands.
 
 ## Time-to-live (TTL)
 
-Azure Cosmos DB supports a time-to-live (TTL) based on the timestamp of the document. TTL can be enabled for collections by going to the [Azure portal](https://portal.azure.com).
+Azure Cosmos DB supports a time-to-live (TTL) based on the timestamp of the document. TTL can be enabled for collections from the [Azure portal](https://portal.azure.com).
 
 ## Transactions
 
@@ -577,5 +577,5 @@ Some applications rely on a [Write Concern](https://docs.mongodb.com/manual/refe
 - Learn how to [use Robo 3T](connect-using-robomongo.md) with Azure Cosmos DB's API for MongoDB.
 - Explore MongoDB [samples](nodejs-console-app.md) with Azure Cosmos DB's API 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 using vCores or vCPUs](../convert-vcore-to-request-unit.md) 
+    - If all you know is the number of vCores and servers in your existing database cluster, read about [estimating request units using vCores or vCPUs](../convert-vcore-to-request-unit.md) 
     - If you know typical request rates for your current database workload, read about [estimating request units using Azure Cosmos DB capacity planner](estimate-ru-capacity-planner.md)
diff --git a/articles/cosmos-db/mongodb/feature-support-42.md b/articles/cosmos-db/mongodb/feature-support-42.md
@@ -4,7 +4,7 @@ description: Learn about Azure Cosmos DB API for MongoDB 4.2 server version supp
 ms.service: cosmos-db
 ms.subservice: cosmosdb-mongo
 ms.topic: overview
-ms.date: 02/23/2022
+ms.date: 04/05/2022
 author: gahl-levy
 ms.author: gahllevy
 ---
@@ -431,7 +431,7 @@ In an [upgrade scenario](upgrade-mongodb-version.md), documents written prior to
 |---------|---------|
 | TTL | Yes |
 | Unique | Yes |
-| Partial | No |
+| Partial | Only supported with unique indexes |
 | Case Insensitive | No |
 | Sparse | No |
 | Background | Yes |
@@ -458,7 +458,7 @@ In an [upgrade scenario](upgrade-mongodb-version.md), documents written prior to
 
 | Command | Supported |
 |---------|---------|
-| $expr | No |
+| $expr | Yes |
 | $jsonSchema | No |
 | $mod | Yes |
 | $regex | Yes |
@@ -595,7 +595,7 @@ Azure Cosmos DB does not yet support server-side sessions commands.
 
 ## Time-to-live (TTL)
 
-Azure Cosmos DB supports a time-to-live (TTL) based on the timestamp of the document. TTL can be enabled for collections by going to the [Azure portal](https://portal.azure.com).
+Azure Cosmos DB supports a time-to-live (TTL) based on the timestamp of the document. TTL can be enabled for collections from the [Azure portal](https://portal.azure.com).
 
 ## Transactions
 
@@ -615,5 +615,5 @@ Some applications rely on a [Write Concern](https://docs.mongodb.com/manual/refe
 - Learn how to [use Robo 3T](connect-using-robomongo.md) with Azure Cosmos DB API for MongoDB.
 - Explore MongoDB [samples](nodejs-console-app.md) with Azure Cosmos DB API 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 using vCores or vCPUs](../convert-vcore-to-request-unit.md). 
+    - If all you know is the number of vCores and servers in your existing database cluster, read about [estimating request units using vCores or vCPUs](../convert-vcore-to-request-unit.md). 
     - If you know typical request rates for your current database workload, read about [estimating request units using Azure Cosmos DB capacity planner](estimate-ru-capacity-planner.md).
diff --git a/articles/cosmos-db/mongodb/mongodb-indexing.md b/articles/cosmos-db/mongodb/mongodb-indexing.md
@@ -5,7 +5,7 @@ ms.service: cosmos-db
 ms.subservice: cosmosdb-mongo
 ms.devlang: javascript
 ms.topic: how-to
-ms.date: 10/13/2021
+ms.date: 4/5/2022
 author: gahl-levy
 ms.author: gahllevy
 ms.custom: devx-track-js, cosmos-db-video
@@ -203,9 +203,6 @@ The following operations are common for accounts serving wire protocol version 4
 
 [Unique indexes](../unique-keys.md) are useful for enforcing that two or more documents do not contain the same value for indexed fields.
 
-> [!IMPORTANT]
-> Unique indexes can be created only when the collection is empty (contains no documents).
-
 The following command creates a unique index on the field `student_id`:
 
 ```shell
@@ -244,6 +241,43 @@ In the preceding example, omitting the ```"university":1``` clause returns an er
 
 `cannot create unique index over {student_id : 1.0} with shard key pattern { university : 1.0 }`
 
+#### Limitations
+
+On accounts that have continuous backup or synapse link enabled, unique indexes will need to be created while the collection is empty.
+
+#### Unique partial indexes
+
+Unique partial indexes can be created by specifying a partialFilterExpression along with the 'unique' constraint in the index. This results in the unique constraint being applied only to the documents that meet the specified filter expression.
+
+The unique constraint will not be effective for documents that do not meet the specified criteria. As a result, other documents will not be prevented from being inserted into the collection.
+
+This feature is supported with the Cosmos DB API for MongoDB versions 3.6 and above.
+
+To create a unique partial index from Mongo Shell, use the command `db.collection.createIndex()` with the 'partialFilterExpression' option and 'unique' constraint.
+The partialFilterExpression option accepts a json document that specifies the filter condition using:
+
+* equality expressions (i.e. field: value or using the $eq operator),
+*'$exists: true' expression,
+* $gt, $gte, $lt, $lte expressions,
+* $type expressions,
+* $and operator at the top-level only
+
+The following command creates an index on collection `books` that specifies a unique constraint on the `title` field and a partial filter expression `rating: { $gte: 3 }`:
+
+```shell
+db.books.createIndex( 
+   { title: 1 }, 
+   { unique: true, partialFilterExpression: { rating: { $gte: 3 } } } 
+) 
+```
+
+To delete a partial unique index using om Mongo Shell, use the command `getIndexes()` to list the indexes in the collection.
+Then drop the index with the following command:
+
+```shell
+db.books.dropIndex("indexName")
+```
+
 ### TTL indexes
 
 To enable document expiration in a particular collection, you need to create a [time-to-live (TTL) index](../time-to-live.md). A TTL index is an index on the `_ts` field with an `expireAfterSeconds` value.
