topic Re: when automatic liquid clustering is enabled, how to know which columns are used for clustering? in Data Engineering

when automatic liquid clustering is enabled, how to know which columns are used for clustering?

smoortema — Wed, 22 Oct 2025 12:00:18 GMT

Let's say a table is configured to have automatic liquid clustering:

ALTER TABLE table1 CLUSTER BY AUTO;

How to know which columns were chosen by Databricks?

Re: when automatic liquid clustering is enabled, how to know which columns are used for clustering?

szymon_dybczak — Wed, 22 Oct 2025 12:06:54 GMT

You can use DESCRIBE TABLE or SHOW TBLPROPERTIES. If automatic liquid clustering is enabled, the clusterByAuto property is set to true. The clusteringColumns property shows the current clustering columns that were automatically or manually selected.

Use liquid clustering for tables | Databricks on AWS

Re: when automatic liquid clustering is enabled, how to know which columns are used for clustering?

smoortema — Wed, 22 Oct 2025 12:15:07 GMT

Is there a way to set up automatic clustering by giving it a hint to use certain columns until Databricks has enough history to choose one?

Re: when automatic liquid clustering is enabled, how to know which columns are used for clustering?

szymon_dybczak — Wed, 22 Oct 2025 12:17:02 GMT

Unfortunately there is no option for doing that currently. But it seems like a really good idea for a product team to consider 🙂

Re: when automatic liquid clustering is enabled, how to know which columns are used for clustering?

smoortema — Wed, 22 Oct 2025 12:46:49 GMT

From the documentation, it seems that in Python, there is such an option, only when creating or replacing a table.

# To set clustering columns and auto, which serves as a way to give a hint # for the initial selection. df.writeTo(...).using("delta") .clusterBy("clusteringColumn1", "clusteringColumn2") .option(“clusterByAuto”, “true”) .create()

Re: when automatic liquid clustering is enabled, how to know which columns are used for clustering?

szymon_dybczak — Wed, 22 Oct 2025 13:20:54 GMT

Thanks for letting me know. I wasn't aware of that 🙂