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Analyze Slow Queries

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  • Performance Advisor
  • Query Profiler
  • Real-Time Performance Panel (RTPP)
  • Best Practices for Query Performance

Atlas provides several tools to help analyze slow queries executed on your clusters. See the following sections for descriptions of each tool. To optimize your query performance, review the best practices for query performance.

The Performance Advisor monitors queries that MongoDB considers slow and suggests new indexes to improve query performance.

You can use the Performance Advisor to review the following information:

The Query Profiler displays slow-running operations and their key performance statistics. You can explore a sample of historical queries for up to the last 24 hours without additional cost or performance overhead. Before you enable the Query Profiler, see Considerations.

The Real-Time Performance Panel identifies relevant database operations, evaluates query execution times, and shows the ratio of documents scanned to documents returned during query execution. RTPP is enabled by default.

Important

To optimize query performance, review the following best practices:

  • Create queries that your current indexes support to reduce the time needed to search for your results.
  • Avoid creating documents with large array fields that require a lot of processing to search and index.
  • Optimize your indexes and remove unused or inefficent indexes. Too many indexes can negatively impact write performance.
  • Consider the suggested indexes from the Performance Advisor with the highest Impact scores and lowest Average Query Targeting scores.
  • Create the indexes that the Performance Advisor suggests when they align with your Indexing Strategies.
  • The Performance Advisor cannot suggest indexes for MongoDB databases configured to use the ctime timestamp format. As a workaround, set the timestamp format for such databases to either iso8601-utc or iso8601-local.
  • Perform rolling index builds to reduce the performance impact of building indexes on replica sets and sharded clusters.
  • Drop unused, redundant, and hidden indexes to improve write performance and free storage space.
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