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创建和管理 Streaming Query

This page describes how to create and manage streaming queries in HStream Platform.

Create a query

First, navigate to the Queries page and click the Create query button to go to the Create query page.

In this page, you can see 3 areas used throughout the creation process:

  • The Stream Catalog area on the left is used to select the streams you want to use in the query.
  • The Query Editor area on the top right is used to write the query.
  • The Query Result area on the bottom right is used to display the query result.

Below sections describe how these areas are used in the creation process.

Stream Catalog

The Stream Catalog will display all the streams as a list. You can use one of them as the source stream of the query. For example, if a stream is test, after selecting it, the Query Editor will be filled with the following query:

sql
CREATE STREAM stream_iyngve AS SELECT * FROM test;

This can help you quickly create a query. You can also change the query to meet your needs.

TIP

The auto-generated query is commented by default. You need to uncomment it to make it work.

INFO

The auto-generated query will generate a stream with a stream_ prefix and a random suffix after creating it. You can change the name of the stream to meet your needs.

Query Editor

The Query Editor is used to write the query.

Besides the textarea, there are still a right sidebar to assist you in writing the query. To create a query, you need to provide a Query name to identify the query, an text field in the right sidebar will automatically generate a query name for you. You can also change it to meet your needs.

Once you finish writing the query, click the Save & Run button to create the query and run it.

Query Result

After creating the query, the Query Result area will display the query result in real time.

The query result is displayed in a table. Each row represents a record in the stream. You can refer to Get Records to learn more about the record.

If you want to stop viewing the query result, you can click the Cancel button to stop it. For re-viewing the query result, you can click the View Live Result button to view again.

INFO

When creating a materialized view, it will internally create a query and its result is the view. So the query result is the same as the view result.

View queries

The Queries page displays all the queries in your account. For each query, you can view the following information:

  • The Name of the query.

  • The Created time of the query.

  • The Status of the query.

  • The SQL of the query.

  • Actions, which for the extra operations of the query:

    • Terminate: Terminate the query.
    • Duplicate: Duplicate the query.
    • Delete: Delete the query.

To view a specific query, you can click the Name of the query to go to the details page.

View query details

The details page displays the detailed information of a query:

  1. All the information in the queries page.

  2. Different tabs are provided to display the related information of the query:

    • Overview: Besides the basic information, also can view the metrics of the query.
    • SQL: View the SQL of the query.

View query overview

The Overview page displays the metrics of a query. The default duration is last 5 minutes. You can select different durations to control the time range of the metrics:

  • last 5 minutes
  • last 1 hour
  • last 3 hours
  • last 6 hours
  • last 12 hours
  • last 1 day
  • last 3 days
  • last 1 week

The metrics of the query include (with last 5 minutes as an example), from left to right:

  • Input records throughput: The number of records that the query receives from the source stream per second.
  • Output records throughput: The number of records that the query outputs to the result stream per second.
  • Total records: The number of records to the query in the last 5 minutes. Including input and output records.
  • Execution errors: The number of errors that the query encounters in the last 5 minutes.

View query SQL

The SQL page displays the SQL of a query. You can only view the SQL of the query, but cannot edit it.

Delete a query

This section describes how to delete a query.

Delete a query from the Queries page

  1. Navigate to the Queries page.
  2. Click the Delete icon of the query you want to delete. A confirmation dialog will pop up.
  3. Confirm the deletion by clicking the Confirm button in the dialog.

Delete a query from the Query Details page

  1. Navigate to the details page of the query you want to delete.
  2. Click the Delete button. A confirmation dialog will pop up.
  3. Confirm the deletion by clicking the Confirm button in the dialog.