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Cover image for Unlocking KQL: Learning from all the queries
Bala Madhusoodhanan
Bala Madhusoodhanan

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Unlocking KQL: Learning from all the queries

Intro:
Building on the basics covered in our previous post, we'll dive into more complex queries, real-world scenarios, and optimization techniques to enhance your data analysis skills in Azure Application Insights.

Some more Commands
KQL offers a range of advanced commands that allow for more complex data manipulation and analysis. Here are some of the key commands:

take: Limits the number of rows returned.

customEvents
| take 10
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Use Case: Quickly previewing a small subset of data.

sort: Orders rows based on a specified column.

customEvents
| where cloud_RoleInstance == "Chatbot instance name" 
| take 50
| sort by timestamp desc 
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Use Case: Sorting requests by the most recent timestamp.

Optimizing Queries

Tips for Efficient Querying:

After numerous trials and errors, and diligently writing KQL queries while adhering to best practices, I've found that structuring the query as outlined above yields the most efficient and effective results. This approach ensures optimal performance by filtering data early, minimizing unnecessary data movement, and leveraging appropriate operators. By following these guidelines, you can achieve more accurate and faster query execution, making your data analysis in Azure Application Insights both powerful and streamlined. 😊

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  • Use Filters Early: Apply where clauses early in the query to reduce the dataset size.

  • Minimize Data Movement: Avoid unnecessary data movement by using appropriate operators.

  • Leverage Aggregations: Use summarize to aggregate data and reduce the volume of data processed.

Common Pitfalls and How to Avoid Them:

  • Large Dataset Processing: Avoid processing large datasets without filtering. Use where clauses to limit the data.
  • Unnecessary Columns: Use project to select only the necessary columns, reducing the amount of data processed.

Further Read:
Best Practices - KQL

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