Issue with SQL Aggregation in StarRocks Database: Empty Fields in Qlik Sense

korsikov — Wed, 02 Apr 2025 14:19:59 GMT

We are experiencing an issue when loading data from a StarRocks database into Qlik Sense November 2024 U8. Specifically, when we apply any SQL aggregation function (such as char_length() or concat()) on a field containing long text, Qlik Sense returns empty values (not NULL) for fields where the text length exceeds approximately 190 characters.

Details:

If we load raw data into Qlik Sense without any SQL aggregation, all text values are correctly loaded, regardless of length.
If we perform any SQL-level transformation (e.g., char_length(texts), concat(texts, id), etc.), fields with more than ~190 characters return as empty.
This issue is independent of the MySQL driver version (tested with MySQL 8 and 9.2 drivers).
The same database schema works fine in Microsoft SQL Server (no missing values).
The texts column is defined as VARCHAR(1048567) and does not contain null bytes.
The issue is consistent across different Qlik Sense versions.

Example: Working query (raw data loads correctly):

[Sample2]: Load id, texts, len(texts) as len; select id, texts from test.sample;

Problematic query (results in empty values for long texts):

[Sample2]: Load *; select id, texts, char_length(texts) as len from test.sample;

After executing the second query, Qlik Sense shows empty values for the texts field where the character length is greater than ~190.

Questions:

Is there a known limitation in Qlik Sense when handling long text fields with SQL aggregations?
Are there specific settings or best practices to prevent data truncation or empty values when performing SQL-level calculations?
Could this be related to internal buffer limits or encoding differences in how Qlik handles StarRocks data?

We would appreciate any guidance on resolving this issue.

topic Issue with SQL Aggregation in StarRocks Database: Empty Fields in Qlik Sense in App Development

Issue with SQL Aggregation in StarRocks Database: Empty Fields in Qlik Sense