We are experiencing troubles with loading data to Snowflake, probably related to null values in columns set as PK. The issue causes some jobs to fail with the error "NULL result in a non-nullable column" or similar. The issue affects different snowflake components (transformations, writer)
We're investigating the causes for this issue. Next update in one hour.
UPDATE 8:40 UTC: We are still investigating the problem. We managed to reproduce the problem in a test and are performing other steps to find the root cause. Next update in one hour.
UPDATE 9:00 UTC: The root cause of the problem is the fact that Snowflake did not implement NOT NULL constraint on columns set as primary keys in the past but started to enforce it in the latest release. See this announcement for further details: https://docs.snowflake.com/en/release-notes/2021-06-bcr.html#create-table-command-change-to-enforcement-of-primary-keys-created-by-command
You can fix the problem immediately by removing the null values from columns set as primary keys. We are talking to Snowflake support if it is possible to put back the behavior for selected tables or databases for customers who cannot fix it easily now (as it would e.g. break some incremental loading settings) so please reach us at support@keboola.com if you are in such situation.
UPDATE 10:00 UTC: We were able to roll back this change with Snowflake support and postpone it for four weeks, giving you time to prepare your data. If you are running your own Snowflake warehouse you will need to disable this change on your own.
UPDATE 11:02 UTC: We've verified in multiple jobs that the issue has been resolved on all our Snowflake accounts.
Unfortunately, there were cases where the issue was not mitigated. The reason is that the change has been released worldwide to all Snowflake clients. So if you're using your own Snowflake account in Keboola (either as backend or in Snowflake writer), you need to rollback the release bundle on your Snowflake account as well.
You need to run the following query on your Snowflake instance
SELECT SYSTEM$DISABLE_BEHAVIOR_CHANGE_BUNDLE('2021_05');
You will need ACCOUNTADMIN role to do that. This will temporarily rollback the problematic behavior. We will either provide a fix on platform level if possible or publish a migration guide to mitigate this once this change will be reenabled in approximately 4 weeks.