Monitor Azure Cosmos DB data by using diagnostic settings in Azure

APPLIES TO: NoSQL MongoDB Cassandra Gremlin Table

Diagnostic settings in Azure are used to collect resource logs. Azure resource Logs are emitted by a resource and provide rich, frequent data about the operation of that resource. These logs are captured per request and they're also referred to as "data plane logs". Some examples of the data plane operations include delete, insert, and readFeed. The content of these logs varies by resource type.

Platform metrics and the Activity logs are collected automatically, whereas you must create a diagnostic setting to collect resource logs or forward them outside of Azure Monitor. You can turn on diagnostic setting for Azure Cosmos DB accounts and send resource logs to the following sources:

• Log Analytics workspaces
  • Data sent to Log Analytics can be written into Azure Diagnostics (legacy) or Resource-specific (preview) tables
• Event hub
• Storage Account

Note

We recommend creating the diagnostic setting in resource-specific mode (for all APIs except API for Table) following our instructions for creating diagnostics setting via REST API. This option provides additional cost-optimizations with an improved view for handling data.

Create diagnostic settings

Azure portal

1. Sign into the Azure portal.

2. Navigate to your Azure Cosmos DB account. Open the Diagnostic settings pane under the Monitoring section, and then select Add diagnostic setting option.

   

3. In the Diagnostic settings pane, fill the form with your preferred categories. Included here's a list of log categories.

   Category	API	Definition	Key Properties
   DataPlaneRequests	All APIs	Logs back-end requests as data plane operations, which are requests executed to create, update, delete or retrieve data within the account.	Requestcharge, statusCode, clientIPaddress, partitionID, resourceTokenPermissionId resourceTokenPermissionMode
   MongoRequests	Mongo	Logs user-initiated requests from the front end to serve requests to Azure Cosmos DB for MongoDB. When you enable this category, make sure to disable DataPlaneRequests.	Requestcharge, opCode, retryCount, piiCommandText
   CassandraRequests	Cassandra	Logs user-initiated requests from the front end to serve requests to Azure Cosmos DB for Cassandra. When you enable this category, make sure to disable DataPlaneRequests.	operationName, requestCharge, piiCommandText
   GremlinRequests	Gremlin	Logs user-initiated requests from the front end to serve requests to Azure Cosmos DB for Gremlin. When you enable this category, make sure to disable DataPlaneRequests.	operationName, requestCharge, piiCommandText, retriedDueToRateLimiting
   QueryRuntimeStatistics	NoSQL	This table details query operations executed against an API for NoSQL account. By default, the query text and its parameters are obfuscated to avoid logging personal data with full text query logging available by request.	databasename, partitionkeyrangeid, querytext
   PartitionKeyStatistics	All APIs	Logs the statistics of logical partition keys by representing the estimated storage size (KB) of the partition keys. This table is useful when troubleshooting storage skews. This PartitionKeyStatistics log is only emitted if the following conditions are true: 1. At least 1% of the documents in the physical partition have same logical partition key. 2. Out of all the keys in the physical partition, the top three keys with largest storage size are captured by the PartitionKeyStatistics log. If the previous conditions aren't met, the partition key statistics data isn't available. It's okay if the above conditions aren't met for your account, which typically indicates you have no logical partition storage skew. Note: The estimated size of the partition keys is calculated using a sampling approach that assumes the documents in the physical partition are roughly the same size. If the document sizes aren't uniform in the physical partition, the estimated partition key size may not be accurate.	subscriptionId, regionName, partitionKey, sizeKB
   PartitionKeyRUConsumption	API for NoSQL	Logs the aggregated per-second RU/s consumption of partition keys. This table is useful for troubleshooting hot partitions. Currently, Azure Cosmos DB reports partition keys for API for NoSQL accounts only and for point read/write and stored procedure operations.	subscriptionId, regionName, partitionKey, requestCharge, partitionKeyRangeId
   ControlPlaneRequests	All APIs	Logs details on control plane operations, which include, creating an account, adding or removing a region, updating account replication settings etc.	operationName, httpstatusCode, httpMethod, region
   TableApiRequests	API for Table	Logs user-initiated requests from the front end to serve requests to Azure Cosmos DB for Table. When you enable this category, make sure to disable DataPlaneRequests.	operationName, requestCharge, piiCommandText

4. Once you select your Categories details, then send your Logs to your preferred destination. If you're sending Logs to a Log Analytics Workspace, make sure to select Resource specific as the Destination table.

   

Azure CLI

Use the az monitor diagnostic-settings create command to create a diagnostic setting with the Azure CLI. See the documentation for this command for descriptions of its parameters.

Note

If you are using API for NoSQL, we recommend setting the export-to-resource-specific property to true.

1. Create shell variables for subscriptionId, diagnosticSettingName, workspaceName and resourceGroupName.

   # Variable for subscription id
   subscriptionId="<subscription-id>"
   
   # Variable for resource group name
   resourceGroupName="<resource-group-name>"
   
   # Variable for workspace name
   workspaceName="<workspace-name>"
   
   # Variable for diagnostic setting name
   diagnosticSettingName="<diagnostic-setting-name>"
   

2. Use az monitor diagnostic-settings create to create the setting.

   az monitor diagnostic-settings create \
       --resource "/subscriptions/$subscriptionId/resourceGroups/$resourceGroupName/providers/Microsoft.DocumentDb/databaseAccounts/" \
       --name $diagnosticSettingName \
       --export-to-resource-specific true \
       --logs '[{"category": "QueryRuntimeStatistics","categoryGroup": null,"enabled": true,"retentionPolicy": {"enabled": false,"days": 0}}]' \
       --workspace "/subscriptions/$subscriptionId/resourcegroups/$resourceGroupName/providers/microsoft.operationalinsights/workspaces/$workspaceName"
   

REST API

Use the Azure Monitor REST API for creating a diagnostic setting via the interactive console.

Note

We recommend setting the logAnalyticsDestinationType property to Dedicated for enabling resource specific tables.

1. Create an HTTP PUT request.

   PUT
   https://management.azure.com/{resource-id}/providers/microsoft.insights/diagnosticSettings/service?api-version={api-version}
   

2. Use these headers with the request.

   Parameters/Headers	Value/Description
   name	The name of your diagnostic setting.
   resourceUri	Microsoft Insights subresource URI for Azure Cosmos DB account.
   api-version	2017-05-01-preview
   Content-Type	application/json

   Note

   The URI for the Microsoft Insights subresource is in this format: subscriptions/{SUBSCRIPTION_ID}/resourceGroups/{RESOURCE_GROUP}/providers/Microsoft.DocumentDb/databaseAccounts/{ACCOUNT_NAME}/providers/microsoft.insights/diagnosticSettings/{DIAGNOSTIC_SETTING_NAME}. For more information about Azure Cosmos DB resource URIs, see resource URI syntax for Azure Cosmos DB REST API.

3. Set the body of the request to this JSON payload.

   {
       "id": "/subscriptions/{SUBSCRIPTION_ID}/resourceGroups/{RESOURCE_GROUP}/providers/Microsoft.DocumentDb/databaseAccounts/{ACCOUNT_NAME}/providers/microsoft.insights/diagnosticSettings/{DIAGNOSTIC_SETTING_NAME}",
       "type": "Microsoft.Insights/diagnosticSettings",
       "name": "name",
       "location": null,
       "kind": null,
       "tags": null,
       "properties": {
           "storageAccountId": null,
           "serviceBusRuleId": null,
           "workspaceId": "/subscriptions/{SUBSCRIPTION_ID}/resourcegroups/{RESOURCE_GROUP}/providers/microsoft.operationalinsights/workspaces/{WORKSPACE_NAME}",
           "eventHubAuthorizationRuleId": null,
           "eventHubName": null,
           "logs": [
               {
                   "category": "DataPlaneRequests",
                   "categoryGroup": null,
                   "enabled": true,
                   "retentionPolicy": {
                       "enabled": false,
                       "days": 0
                   }
               },
               {
                   "category": "QueryRuntimeStatistics",
                   "categoryGroup": null,
                   "enabled": true,
                   "retentionPolicy": {
                       "enabled": false,
                       "days": 0
                   }
               },
               {
                   "category": "PartitionKeyStatistics",
                   "categoryGroup": null,
                   "enabled": true,
                   "retentionPolicy": {
                       "enabled": false,
                       "days": 0
                   }
               },
               {
                   "category": "PartitionKeyRUConsumption",
                   "categoryGroup": null,
                   "enabled": true,
                   "retentionPolicy": {
                       "enabled": false,
                       "days": 0
                   }
               },
               {
                   "category": "ControlPlaneRequests",
                   "categoryGroup": null,
                   "enabled": true,
                   "retentionPolicy": {
                       "enabled": false,
                       "days": 0
                   }
               }
           ],
           "logAnalyticsDestinationType": "Dedicated"
       },
       "identity": null
   }
   

Enable full-text query for logging query text

Note

Enabling this feature may result in additional logging costs, for pricing details visit Azure Monitor pricing. It is recommended to disable this feature after troubleshooting.

Azure Cosmos DB provides advanced logging for detailed troubleshooting. By enabling full-text query, you’ll be able to view the deobfuscated query for all requests within your Azure Cosmos DB account. You’ll also give permission for Azure Cosmos DB to access and surface this data in your logs.

Azure portal

1. To enable this feature, navigate to the Features page in your Azure Cosmos DB account.

   

2. Select Enable, this setting will then be applied within the next few minutes. All newly ingested logs will have the full-text or PIICommand text for each request.

   

Azure CLI / REST API

1. Ensure you're logged in to the Azure CLI. For more information, see sign in with Azure CLI. Optionally, ensure that you've configured the active subscription for your CLI. For more information, see change the active Azure CLI subscription.

2. Create shell variables for accountName and resourceGroupName.

   # Variable for resource group name
   resourceGroupName="<resource-group-name>"
   
   # Variable for account name
   accountName="<account-name>"
   

3. Get the unique identifier for your existing account using az show.

   az cosmosdb show \
       --resource-group $resourceGroupName \
       --name $accountName \
       --query id
   

   Store the unique identifier in a shell variable named $uri.

   uri=$(
       az cosmosdb show \
           --resource-group $resourceGroupName \
           --name $accountName \
           --query id \
           --output tsv
   )
   

4. Check if full-text query is already enabled by querying the resource using the REST API and az rest with an HTTP GET verb.

   az rest \
       --method GET \
       --uri "https://management.azure.com/$uri/?api-version=2021-05-01-preview" \
       --query "{AccountName:name, FullTextQueryEnabled:properties.diagnosticLogSettings.enableFullTextQuery}"
   

5. If full-text query isn't already enabled, enable it using az rest again with an HTTP PATCH verb and a JSON payload.

   az rest \
       --method PATCH \
       --uri "https://management.azure.com/$uri/?api-version=2021-05-01-preview" \
       --body '{"properties": {"diagnosticLogSettings": {"enableFullTextQuery": "True"}}}'
   

6. Wait a few minutes for the operation to complete. Check the status of full-text query by using az rest again.

   az rest \
       --method GET \
       --uri "https://management.azure.com/$uri/?api-version=2021-05-01-preview" \
       --query "{AccountName:name, FullTextQueryEnabled:properties.diagnosticLogSettings.enableFullTextQuery}"
   

   The output should be similar to this example.

   {
     "AccountName": "<account-name>",
     "FullTextQueryEnabled": "True"
   }
   

Query data

To learn how to query using these newly enabled features, see:

• API for NoSQL
• API for MongoDB
• API for Apache Cassandra
• API for Apache Gremlin

Next steps

• For a reference of the log and metric data, see monitoring Azure Cosmos DB data reference.
• For more information on how to query resource-specific tables, see troubleshooting using resource-specific tables.
• For more information on how to query AzureDiagnostics tables, see troubleshooting using AzureDiagnostics tables.
• For detailed information about how to create a diagnostic setting by using the Azure portal, CLI, or PowerShell, see create diagnostic setting to collect platform logs and metrics in Azure article.