Implement and query Azure Cosmos DB logs

Azure Cosmos DB is a globally distributed, multi-model database service from Microsoft that offers robust and scalable data management solution. A vital part of maintaining and managing any database system is working effectively with its logs, and Azure Cosmos DB is no exception.

The beauty of Azure Cosmos DB is that it provides extensive logging capabilities that enable developers and administrators to monitor, troubleshoot, and optimize their database applications. This includes the ability to collect logs, metrics, and diagnose issues – this article will guide through how to implement and query Azure Cosmos DB logs.

Implementing Azure Cosmos DB Logs

Before you can query logs, it’s vital to set up Azure Cosmos DB to collect and store the necessary log data. Follow these steps to implement Azure Cosmos DB logs:

Step 1: Enable Diagnostics Settings

You need to enable diagnostics settings for your Azure Cosmos DB account. This is done through the Azure portal, where you can navigate through Monitor -> Diagnostics settings. Here, you can turn on the Azure Cosmos DB logs you want to collect.

Step 2: Select Log Categories

Azure Cosmos DB provides several log categories, and you can choose which ones you want based on your requirements. These categories include:

• Data Plane Requests: Logs every request made against your Azure Cosmos account.
• Query Runtime Statistics: Provides detailed metrics about your queries.
• Control Plane Requests: Logs every operation against your Azure Cosmos account configuration.
• Partition Key Statistics: Provides metrics about partition key ranges.
• Mongo Requests: Logs every operation made against an Azure Cosmos account configured with MongoDB API.

Step 3: Set Destination

Next, decide where you want to send your logs. You have a number of options including:

• Send to Log Analytics workspace: Send logs to a Log Analytics workspace, where you can use Log Analytics to query and analyze the logs.
• Stream to an event hub: Stream logs to an event hub for custom processing or ingestion to third-party services.
• Archive to a storage account: Archive logs to a storage account for long-term retention.

Querying Azure Cosmos DB Logs

Once you have implemented Azure Cosmos DB logs and defined where they are stored, you can query these logs. Azure Monitor Logs and its associated query language—Kusto Query Language (KQL)—is the tool to query logs in a Log Analytics workspace.

For instance, the following query returns the total count of requests to a Cosmos DB account over the past day:

AzureDiagnostics
| where TimeGenerated > ago(24h)
| where Category == "DataPlaneRequests"
| summarize Count=sum(requestCharge_s)

This query will summarize the total number of requests that received a 429 (Rate Limit Exceeded) response:

AzureDiagnostics
| where TimeGenerated > ago(24h)
| where Category == "DataPlaneRequests" and responseStatusCode_s == "429"
| summarize Count=Count()

Conclusion

Implementing and querying Azure Cosmos DB logs is crucial to understand performance patterns, identify issues, and optimize database operations. Azure provides various utilities, such as Azure Monitor and Kusto Query Language, to help developers efficiently manage the logs and extract valuable insights. As you prepare for the DP-420 exam, developing a clear understanding of Azure Cosmos DB log implementation and querying should be an essential part of your strategy.

Practice Test

True or False: Azure Cosmos DB provides logs to perform diagnostic and troubleshooting tasks.

• True
• False

Answer: True

Explanation: Azure Cosmos DB provides logs which contains detailed information about operations, errors, and metrics, which are useful for both diagnostic and troubleshooting tasks.

Which type of logs does Azure Cosmos DB provide?

• A. Data Plane Logs
• B. Diagnostic Logs
• C. Both A and B
• D. None of the above

Answer: C. Both A and B

Explanation: Azure Cosmos DB provides two types of logs, Data Plane Logs and Diagnostic Logs. Data Plane Logs contain information about the operations performed on the data, and Diagnostic Logs provide performance information and metrics.

True or False: Azure Cosmos DB Data Plane Logs do not contain any detailed information about the request and response bodies.

• True
• False

Answer: True

Explanation: Azure Cosmos DB Data Plane Logs contain detailed information about operations, including operation types, status codes, and durations, but do not include detailed information about the request and response bodies.

Which of the following are needed to enable Azure Cosmos DB logs?

• A. Azure Monitor
• B. Azure Storage Account
• C. Azure Event Hubs
• D. All of the above

Answer: D. All of the above

Explanation: To enable Azure Cosmos DB logging, you need an Azure Monitor to view the logs, an Azure Storage account to store the logs, and Azure Event Hubs to stream real-time logs.

True or False: Azure Cosmos DB Diagnostic Logs are automatically enabled when a database is created.

• True
• False

Answer: False

Explanation: Diagnostic Logs in Azure Cosmos DB are not automatically enabled when a database is created. They must be manually enabled by the user.

Which of the following is not a category of Azure Cosmos DB Diagnostic Logs?

• A. Data Plane Requests
• B. Control Plane Requests
• C. Metric Requests
• D. Database Creation Requests

Answer: D. Database Creation Requests

Explanation: The three categories of Azure Cosmos DB Diagnostic Logs are Data Plane Requests, Control Plane Requests, and Metric Requests.

True or False: Azure Cosmos DB logs can be exported to Log Analytics for further analysis.

• True
• False

Answer: True

Explanation: Azure Cosmos DB logs can be exported to Log Analytics, which allows for more complex query capabilities and analysis, and integration with other Azure services’ logs.

What is the standard retention period for Azure Cosmos DB Diagnostic Logs?

• A. 30 days
• B. 60 days
• C. 90 days
• D. Unlimited

Answer: A. 30 days

Explanation: Azure Cosmos DB Diagnostic Logs are kept for 30 days. After this, the logs are automatically deleted unless the user has configured a different retention period.

True or False: Azure Cosmos DB Diagnostic Logs include information about successful and failed requests.

• True
• False

Answer: True

Explanation: Azure Cosmos DB Diagnostic Logs provide detailed information on all requests, regardless of whether they were successful or not. This includes the request URI, status code, and duration.

Which tool can be used to view real-time Azure Cosmos DB logs?

• A. Azure Monitor
• B. Azure Storage Account
• C. Azure Event Hubs
• D. Azure SQL Database

Answer: A. Azure Monitor

Explanation: Azure Monitor can be used to view real-time Azure Cosmos DB logs. It helps you understand how your applications are performing and proactively identifies issues affecting them and the resources they depend on.

Interview Questions

What is Azure Cosmos DB?

Azure Cosmos DB is a globally distributed, multi-model database service provided by Microsoft for managing highly responsive and scalable data on the Azure platform.

What is the significance of Azure Cosmos DB logs?

Azure Cosmos DB logs provide detailed diagnostic and troubleshooting information, helping in monitoring, troubleshooting, and optimizing the performance of Azure Cosmos DB.

What are some types of logs available in Azure Cosmos DB?

Azure Cosmos DB provides various types of logs such as Data Plane Logs, Query Runtime Stats (formerly QueryExecutionStats), and Metrics Logs.

How do you enable logs in Azure Cosmos DB?

To enable logs, navigate to the Diagnostics settings for Azure Cosmos DB. Then, add a new setting, select the logs you want to collect and specify the destination for log data.

Where can you send Azure Cosmos DB logs?

Azure Cosmos DB logs can be sent to Log Analytics workspace, Azure Storage Account, and Event Hubs.

Can you implement Azure Cosmos DB logs using Azure CLI?

Yes, you can implement Azure Cosmos DB logs using Azure CLI.

How can you implement Azure Cosmos DB logs with Azure CLI?

You can use ‘az monitor diagnostic-settings create’ command in Azure CLI to create diagnostic settings for Azure Cosmos DB.

What are Query Runtime Statistics in Azure Cosmos DB?

Query Runtime Statistics is a feature in Azure Cosmos DB that provides the runtime execution details of a query, helping in diagnosing and troubleshooting performance issues related to queries.

What information do Data Plane Logs provide?

Data Plane Logs provide details about the operations performed against a specific Azure Cosmos container or database, including the response time, status of the operation, consumed request units, etc.

What is the role of Metrics Logs in Azure Cosmos DB?

Metrics Logs provide telemetry data about the throughput, storage, availability, latency, and consistency of your Azure Cosmos DB account.

How can Azure Cosmos DB logs be queried?

Azure Cosmos DB logs can be queried using Kusto query language (KQL) in Azure Monitor Log Analytics.

What is the significance of partition key in Azure Cosmos DB?

The partition key in Azure Cosmos DB determines the distribution of data and throughput across physical partitions. Selecting the right partition key is crucial for ensuring the scalability and performance of Azure Cosmos DB.

What kind of data does the Azure Cosmos DB QueryExecutionStats log provide?

The QueryExecutionStats log provides information about the query compilation and execution, like the number of documents returned, the total request charge, and the retrieval time.

Can you restrict access to Azure Cosmos DB logs?

Yes, access to Azure Cosmos DB logs can be managed and restricted using Azure role-based access control (RBAC).

What is the maximum data retention period for Azure Cosmos DB logs?

The maximum data retention period for Azure Cosmos DB logs is 730 days.