Do not input private or sensitive data. View Qlik Privacy & Cookie Policy.
Skip to main content

Announcements
Join us in Bucharest on Sept 18th for Qlik's AI Reality Tour! Register Now
cancel
Showing results for 
Search instead for 
Did you mean: 
vapukov
Master II
Master II

MySQL CDC Capture - understanding logic

Hi Team,
I never use Talend CDC for sync databases because prefer use other methods, but now one friend ask me to help and I meet some problem, which not expect.
So,
Connections - created, schemas created
Subscriber created, triggers - all ok
Next step create Job - capture "changes" and split for 3 flow - Insert/Update/Delete
also clean
Leave Job for sometime with regular scheduling ... and it crash by null pointer exception, let go investigate

All Inserts - work fine
All Updates - work also fine, and it work fine - if records was Updated twice - it catch only 1 Update, Perfect!!!
Deletes - as well, until ...

Until at the time between iteration same records was - Updated, and then Deleted
Talend not understand this situation and try to Update records with New data where all columns other than PK - NULLS and forget about NOT NULL constraints.
More - it crash not on UPDATE state, where it possible to manage, but crash on read state, because his own Metadata structure has same NOT NULL constraints.
I create testing Job for illustrate situation
0683p000009MDhj.png  0683p000009MDOY.png  0683p000009MDil.png   0683p000009MDYE.png
Situation is realistic and my question is:
- what Talend think when design trigger based CDC without saving OLD and NEW data?
- or why in this case CDC not do the same as for UPDATE - fetch only delete if records deleted?

0683p000009MDfE.png   0683p000009MDYF.png
Labels (2)
1 Reply
Anonymous
Not applicable

Hello ,

We are supposing that you have read the online document about:TalendHelpCenter:CDC architectural overview

Could you please clarify in which Talend version/edition you are?

Best regards

Sabrina