topic Re: no information on character_maximum_length and is_identity in unity catalog table system.informa in Data Governance

no information on character_maximum_length and is_identity in unity catalog table system.information_schema.columns

lizou — Sat, 31 Dec 2022 19:13:08 GMT

no information on character_maximum_length and is_identity in unity catalog table system.information_schema.columns

table definition example

CREATE TABLE tyable_name (

UniqueID bigint not null GENERATED ALWAYS AS IDENTITY ,

ID varchar(256)

)

looks like the columns table only has basic info such as data type

-- query column info

select *

from system.information_schema.columns

where table_name ='<table>' and table_catalog ='<catalog>'

Re: no information on character_maximum_length and is_identity in unity catalog table system.information_schema.columns

lizou — Tue, 03 Jan 2023 13:30:31 GMT

yes, I created a new managed table in the unity catalog, and the issues remain.

Re: no information on character_maximum_length and is_identity in unity catalog table system.information_schema.columns

Hubert-Dudek — Thu, 05 Jan 2023 13:07:02 GMT

I confirm I have the same issue with the unity catalog: schema tables are missing some information, or they are incorrect. @Prabakar Ammeappin @Kaniz Fatma @Sujitha Ramamoorthy maybe we can escalate to someone from Unity team

Re: no information on character_maximum_length and is_identity in unity catalog table system.information_schema.columns

lizou — Fri, 06 Jan 2023 05:52:33 GMT

another issue is if a column is defined as varchar(50) as example

once a data is loaded, the full_data_type is changed to string. I tested multiple times, and looks like that's also an issue

before

after data loaded with a insert statement

full_data_type is changed

select column_name, full_data_type, data_type, character_maximum_length, ordinal_position, *

from system.information_schema.columns

Re: no information on character_maximum_length and is_identity in unity catalog table system.information_schema.columns

Hubert-Dudek — Fri, 06 Jan 2023 09:13:42 GMT

@Werner Stinckens @Christy Seto @Jose Gonzalez can you help with that issue? It is a really interesting bug and a nice feature once it will work correctly.

Re: no information on character_maximum_length and is_identity in unity catalog table system.information_schema.columns

jose_gonzalez — Thu, 06 Apr 2023 18:21:17 GMT

Adding @Kaniz Fatma and @Suteja Kanuri for visibility

Re: no information on character_maximum_length and is_identity in unity catalog table system.information_schema.columns

Debayan — Mon, 02 Jan 2023 17:36:16 GMT

Hi,

Could you please confirm on the issue here? Also, for reference: https://docs.databricks.com/data-governance/unity-catalog/migrate.html

, please let us know if this helps.

Re: no information on character_maximum_length and is_identity in unity catalog table system.informa

anish2102 — Wed, 24 Jul 2024 09:47:06 GMT

Hello Team,

Still i am facing same issue of value zero in character_maximum_length. Is there any other way we can get character_maximum_length of columns?

When we can expect to resolve this bug?

Re: no information on character_maximum_length and is_identity in unity catalog table system.informa

kaj_hejlesen — Tue, 08 Jul 2025 12:05:16 GMT

@jose_gonzalez The information on Maximum string length appears in the 'Profile' window for each column when viewing it in the Catalog Browser. It seems to be updated when the table is updated. Yet, there still seems no way to get this information programmatically. Are there any query available that does not require us to re-calculate the statistics or a timeline for when it will be added to the information_schema.columns?

Re: no information on character_maximum_length and is_identity in unity catalog table system.informa

Subiksha — Mon, 18 Aug 2025 15:25:13 GMT

if you look at the official document here:
https://docs.databricks.com/gcp/en/sql/language-manual/information-schema/columns

many of them are "Always NULL, reserved for future use."

so I think the feature simply isn't available to use yet. It's seems intentional and not a bug.