E-MapReduce:Manage and analyze queries

Prerequisites

A StarRocks instance is created. For more information, see Create an instance.

Features

• SQL tasks: Includes completed tasks and running tasks.

  • Completed tasks: This feature provides a comprehensive view of all completed queries, including failed queries and queries with syntax errors. You can use this interface for detailed analysis. Note that this feature is subject to the following limitation.

    Note

    Only the first 5,000 results from the last 30 days are shown. To view all query records, see audit logs.

  • Running tasks: This module focuses on large or complex queries that are still running. These queries typically involve large-scale data processing, complex computations, or interactions across multiple databases. They can consume significant computing resources, such as CPU, memory, and I/O, which can affect the performance of other queries in the system. Therefore, real-time monitoring of these queries is essential to maintain system stability and ensure responsiveness.

• Slow queries: This feature lists queries in your StarRocks instance that take a long time to execute and may indicate performance bottlenecks. By identifying and tracking slow queries, you can pinpoint issues that affect database efficiency and optimize them.

  Note

  • By default, a query is listed as a slow query if its execution time exceeds 5,000 ms.

  • Currently, only SELECT queries are identified as slow queries.

  • By default, StarRocks retains slow query records for 30 days or up to 10,000 entries. You can use the available filters to narrow down the results.

Access query pages

SQL tasks

1. Go to the StarRocks Manager page.

   1. Log on to the E-MapReduce console.

   2. In the left navigation pane, choose EMR Serverless > StarRocks.

   3. In the top menu bar, select a region as needed.

   4. Click StarRocks Manager, or click Connect in the Actions column of the created instance.

      For more information on connecting to a StarRocks instance, see Connect to a StarRocks instance by using EMR StarRocks Manager.

2. In the left-side navigation pane, choose Diagnostics and Analytics > SQL Tasks.

3. On the Complete Tasks and Running Tasks tabs, click a Query ID.

   • Complete Tasks: You can view details such as the SQL text, task status, and duration. You can also filter the list by user, SQL type (for example, DQL, DML, DDL, or DCL), and database.

   • Running Tasks: You can monitor key performance metrics for large queries, including the total amount of data scanned, the number of processed rows, and CPU time and memory usage.

Slow queries

1. In the left-side navigation pane, choose Diagnostics and Analytics > Slow query.

2. On the Slow query page, click the Query ID of a query to inspect its details.

   For more information, see Query details.

Query details

On the Slow query list page, click a Query ID to open its details page. This page contains the following sections:

• Query details

  Displays basic information about the query and the SQL statement details.

• Query plan

  The frontend (FE) generates the query plan after parsing the SQL. It organizes the relationships between operators (such as Join, Order, and Aggregation) and provides a high-level view of how the query is executed.

• Query profile

  The backend (BE) generates the query profile after a query is executed. It includes performance data, such as the time taken and the amount of data processed in each step, reflecting the query's actual performance. EMR StarRocks Manager supports visual analysis of the profile. For more information, see Introduction to query profile.

Export query information

You can export specific queries for local analysis. EMR Serverless StarRocks lets you filter queries by a specified time range and then export them.

On the SQL Tasks or Slow query list page, you can filter queries by criteria such as status, execution time, date range, and duration. Then, click the Export icon to save the query information locally.