Debug SQL Draft#

This document explains how to enable deployment debugging to simulate deployment running, check outputs, and verify the business logic of SELECT, INSERT and auxiliary statements. This feature improves development efficiency and reduces the risks of poor data quality.

Background Information#

The deployment debugging feature allows you to verify the correctness of the draft’s FlinkSQL logic in the console of fully managed Flink. During the debugging, data is not written to the result table regardless of the type of the result table. When you use the deployment debugging feature, you can use the upstream online data or local mock data. You can debug complex deployments that include multiple SELECT or INSERT statements, and auxiliary statements such as EXPLAIN. SQL query statements allow you to use UPSERT statements that contain update operations, such as count.


A running session cluster which matches the engine version of the debugged SQL draft.


  • You can debug certain types of FlinkSQL statements. DDL statements are not supported.

  • By default, fully managed Flink reads a maximum of 1,000 data records. If the number of data records that are read by fully managed Flink reaches the upper limit, fully managed Flink stops reading data.


  1. Log in to Ververica Cloud.

  2. On the Dashboard page, locate the workspace you want to manage, click the title of the workspace or this icon ⋮, and select Open Console.

  3. In the left-side navigation pane of the Console, click SQL editor and choose the Drafts tab.

  4. Chose a draft you want to debug and click on the Debug icon.