Intermittent Special Characters ("NANA") for Blank CHAR(2) Field from DB2 z/OS

[shyamkatika]

Hi Team,

We are encountering an issue while replicating data from DB2 z/OS to the target using Qlik Replicate.

In the source DB2 z/OS table, a column with data type CHAR(2) contains blank values (spaces) for several records. However, in the target system, we are observing inconsistent behavior:

• Most records are correctly replicated as blanks
• But for a few records, the same field is populated with unexpected special characters like "NANA"

So, not all blank fields are impacted—only a subset of records shows this issue.

Thanks in Advance

[SachinB]

Hello @shyamkatika ,

Based on the behavior observed—especially the inconsistent replication of blank values—it would be best to investigate this further with deeper analysis.

Could you please raise a support case with Qlik Support for this issue?
Kindly include the following details in the case to help expedite the investigation

• Replicate task logs covering the time of occurrence
• Sample source and target data (including affected and non-affected rows)
• Output of HEX values for the impacted column from the source

SELECT NAME, CCSID
FROM SYSIBM.SYSCOLUMNS
WHERE TBNAME = 'YOUR_TABLE';

• Output of hex value in Snowflake 

SELECT
column_name,
LENGTH(column_name) AS LEN,
HEX_ENCODE(column_name) AS HEX_VAL,
COUNT(*)
FROM your_table
GROUP BY 1,2,3
ORDER BY COUNT(*) DESC;

• Diagnostic package of the task 
  

Regards,

Sachin B

[shyamkatika]

Hi @SachinB 

Thank you for your response. Please find the attached screenshots showing the results of the above queries from both the source (DB2 z/OS) and the target (Snowflake).

[SachinB]

Hello @shyamkatika ,

Based on the analysis so far, the behaviour seen in the target system appears to be related to inconsistencies in the underlying source data rather than a replication issue. Specifically, some of the values that appear as blanks may contain non-standard or non-printable characters at the byte level, which can lead to unexpected results after character set conversion.

To proceed with a deeper investigation and validate this further, could you please raise a support case with Qlik Support with all the requested details?

Regards,
Sachin B

[shyamkatika]

Hi Team, 

As a workaround, since the affected field contains numeric data, I changed the data type to INT and applied an IFNULL transformation. This results in blank and special character values being represented as 0.

Thanks,

Shyam Sundar.