DEEP CLONE fails with [UNRESOLVED_ROUTINE] Cannot resolve routine isNotNull on DBR 16.4

dplatform_user
New Contributor II

‎03-03-2026 01:22 AM - edited ‎03-03-2026 01:26 AM

Hi Databricks Community,
 
I'm encountering an issue when attempting to DEEP CLONE a Delta table on DBR 16.4 that works fine on DBR 13.3.
Error Message:
 
[UNRESOLVED_ROUTINE] Cannot resolve routine `isNotNull` on search path [`system`.`builtin`, `system`.`session`, 'mycatalog.default'].
 
 
When it occurs:
• Running CREATE TABLE ... DEEP CLONE ... on a Delta table with writer version 6
• Table has NOT NULL constraints on all columns and an IDENTITY column
• Table features include: checkConstraints, generatedColumns, identityColumns
What works:
• Same DEEP CLONE works on DBR 13.3
• Other tables without these features clone successfully
Questions:
- Is isNotNull a valid SQL routine in DBR 16.4? Spark seems to resolve it during clone metadata validation.
- Why does this work on DBR 13.3 but fail on DBR 16.4? Is there a change in how Delta validates constraint metadata?
- What's the recommended workaround? Should I create a UC function isNotNull, or drop/recreate constraints using standard SQL?
Context:
• DBR 16.4.x-scala2.12, Delta Lake 3.3.1, Unity Catalog
• Error occurs during DEEP CLONE metadata validation/copy phase
Any insights would be appreciated!