Hi @yzhang ,

Ok, so I forgot that Liquid clustering is not compatible with partitioning. But I've got a couple of question to clarify a bit. You wrote in your reply that you were able to run following command:

ANALYZE TABLE csu_metastore_dev.iceberg.big_file_hcm COMPUTE DELTA STATISTICS

If so, that means that this table is already created. Could you run following command? What you can see in result?
Anything about clusteringColumns?

DESCRIBE DETAIL  csu_metastore_dev.iceberg.big_file_hcm;

If above command return info regarding clusteringCommands then following one won't work.

 df.writeTo(csu_metastore_dev.iceberg.big_file_hcm).using("iceberg").partitionedBy("ingest_date").create()

If you want partition a table that already exists and has Liquid Clustering enabled you need to first turn off Liquid Clustering on that table. 

Use liquid clustering for tables - Azure Databricks | Microsoft Learn