use_managed_iceberg warning popping up for projects that don't use iceberg at all

[graciegoheen]

Describe the bug

dbt projects are seeing the following warning emitted:

Use managed Iceberg tables when table_format is iceberg. When this flag is disabled, UniForm is used instead.
You may opt into the new behavior sooner by setting "flags use_managed _iceberg to 'True" in "dbt_project.yml*.
Visit https://docs-getdbt.com/reference/global-configs/behavior-changes for more information.

even when their project isn't using iceberg at all.

Expected behavior

We should suppress this warning if the user isn't using iceberg.

Additional context

this is the PR that added this flag -> #1146
docs here -> https://docs.getdbt.com/reference/global-configs/databricks-changes#use-managed-iceberg

[benc-db]

@graciegoheen do you have any suggestions how to accomplish that? I'm not sure where in the startup process that this gets evaluated...we might not know yet whether you have iceberg models.

[Siete-F]

The message surprised me also, had to look into the concept and even though I don't use 'iceberg' tables, I have to decide how to get rid of this sudden warning.

I would suggest you adjust the message to make clear that

• you do not necessarily use iceberg tables at the moment, but the warning is generated nonetheless.
• explain a default you can configure to mimic 'traditional' behavior.
• explain what 'UniForm' means... I am using Delta tables in a Unity Catalog and never heard about 'UniForm' which it suggests to be the only alternative beside 'iceberg'.

So, I tested configurations to suppress this warning, This part was still unclear to me:

• table_format: UniForm (not tested)
• flags.use_managed_iceberg: false (doesn't work...)
• flags.use_managed_iceberg: true (this works to suppress warning)

So for anybody wanting a solution now. Configure this in dbt_project.yml:

flags:
  use_managed_iceberg: true

This works, even when you don't use iceberg tables. It doesn't affect anything else, which is stated in the docs:

When you set table_format to iceberg, the use_managed_iceberg flag controls how the table is created.

[benc-db]

yes, setting use_managed_iceberg to true is the simplest way to silence the error, and it only affects when you set table_format as iceberg. I think you could also do: dbt run --warn-error-options '{"silence": ["Deprecations"]}'

[michael-robbins-seek]

Same, we don't have any iceberg tables here yet this started appearing in our logs.

It would be nice if we could only WARN when iceberg tables are actually detected.

[kafkaguru]

We set flags.use_managed_iceberg: false which silenced it for our normal models but dbt seed still produces the warning.
Setting this to true silences it for both models and seeds.

[JulienL3vesque]

I can confirm I’m seeing this issue as well. It was confusing because we are using Delta on Databricks, and I was concerned that setting this flag to true might change the table format from Delta to Iceberg.

[benc-db]

@JulienL3vesque it doesn't do anything unless you set your tables to iceberg.

[Korijn]

We still see this warning even with the flag set to true when running dbt debug.

[dtsjbrown]

We have a customer who is also seeing this false-positive warning when they have their environment setup to correctly use UniForm.

[kyle-kent]

This is also a bug for flags.use_materialization_v2. Setting to false doesn't silence the warning