[Bug] `adapter.get_columns_in_relation` does not work cross database

[jeremyyeo]

Is this a new bug in dbt-redshift?

• [X] I believe this is a new bug in dbt-redshift
• [X] I have searched the existing issues, and I could not find an existing issue for this bug

Current Behavior

Not too sure if this calls for it's own issue but pretty much an extension of #179 - adapter.get_columns_in_relation does not support introspecting a table that is in a different database.

Expected Behavior

Just like #179 - we need to make adapter.get_columns_in_relation work across databases.

Steps To Reproduce

1. Using an RA3 redshift cluster with 2 database (dev and sources_only) add 2 tables.

-- using a connection to database sources_only
create table sources_only.public.source_foo as select 1 id;

-- using a connection to database dev
create table dev.public.source_bar as select 1 id;

2. Connect your dbt project to database dev:

# ~/.dbt/profiles.yml
redshift:
  target: default
  outputs:
    default: 
        type: redshift
        host: ...
        port: 5439
        database: dev
        user: root
        password: ...
        schema: public
        ra3_node: true

3. Add 2 sources:

# models/sources.yml
version: 2
sources:
  - name: from_default_db
    schema: public
    tables:
      - name: source_bar
  - name: from_the_other_db
    database: sources_only
    schema: public
    tables:
      - name: source_foo

4. Add a model to test:

-- models/checker.sql
select * from {{ source('from_the_other_db', 'source_foo') }}
union all
select * from {{ source('from_default_db', 'source_bar') }}

$ dbt compile -s checker
02:42:54  Running with dbt=1.7.9
02:42:55  Registered adapter: redshift=1.7.4
02:42:57  Found 1 model, 2 sources, 0 exposures, 0 metrics, 606 macros, 0 groups, 0 semantic models
02:42:57  
02:43:03  Concurrency: 1 threads (target='rs')
02:43:03  
02:43:03  Compiled node 'checker' is:
select * from "sources_only"."public"."source_foo"
union all
select * from "dev"."public"."source_bar"

$ dbt show -s checker
02:44:36  Running with dbt=1.7.9
02:44:38  Registered adapter: redshift=1.7.4
02:44:40  Found 1 model, 2 sources, 0 exposures, 0 metrics, 606 macros, 0 groups, 0 semantic models
02:44:40  
02:44:46  Concurrency: 1 threads (target='rs')
02:44:46  
02:44:47  Previewing node 'checker':
| id |
| -- |
|  1 |
|  1 |

5. Test out get_columns_in_relation:

-- models/checker.sql
{% set c1 = adapter.get_columns_in_relation(source('from_the_other_db', 'source_foo')) %}
{% set c2 = adapter.get_columns_in_relation(source('from_default_db', 'source_bar')) %}
---------
{{ c1 }}
----------
{{ c2 }}

$ dbt compile -s checker
02:48:36  Running with dbt=1.7.9
02:48:37  Registered adapter: redshift=1.7.4
02:48:39  Found 1 model, 2 sources, 0 exposures, 0 metrics, 606 macros, 0 groups, 0 semantic models
02:48:39  
02:48:44  Concurrency: 1 threads (target='rs')
02:48:44  
02:48:48  Compiled node 'checker' is:


---------
[]
----------
[<Column id (integer)>]

^ We didn't manage to retrieve column id for the source that is in the other database (sources_only).

The reason for that is straightforward - if we look at the get_columns_in_relation implementation and try and run that query straight up in Redshift:

Relevant log output

No response

Environment

- OS: macOS
- Python: 3.11
- dbt-core: 1.7.9
- dbt-redshift: 1.7.4

Additional Context

This results in https://github.com/dbt-labs/dbt-codegen/issues/167 - which further materializes itself in dbt Cloud IDE as users try and use the "generate model" function and find that it doesn't work as expected:

[jeremyyeo]

Looks like svv_redshift_columns (https://docs.aws.amazon.com/redshift/latest/dg/cross-database-overview.html) might be what we want to query here

[HartmannVolker]

We are running into the same issue. We are trying to create the dbt output in an other database than the source data is located. adapter.get_columns_in_relation is not returning any columns for tables located in a different database.

I tracked it down to this line where information_schema."columns" is used. This table only returns information about the current database and therefore returns an empty list of columns for tables located in another database.

Maybe something like this could replace information_schema."coloumns" :

SELECT ordinal_position,
          table_name,
          column_name,
          data_type,
          character_maximum_length,
          numeric_precision,
          numeric_scale
FROM SVV_ALL_COLUMNS  WHERE database_name = '<database>' AND schema_name = '<schema>' AND table_name = '<table>'

[dataders]

We are running into the same issue

@VolkerSchiewe are you also using RA3 nodes?

[HartmannVolker]

We are running into the same issue

@VolkerSchiewe are you also using RA3 nodes?

yes

[dataders]

@VolkerSchiewe @jeremyyeo I just opened #738, do you want to it's version of redshift__get_columns_in_relation()? I'm also going to ask the Redshift team for advice

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[HartmannVolker]

@dataders any update on that topic? Have you talked to the redshift team?

[dataders]

hey @VolkerSchiewe yeah we've been in discussion with them. Have you looked over #742? The consensus between their team and ours right now is that rather than solve one-off issues like this one, we instead holistically address cross-database functionality.

Are you on a team currently that would benefit from this feature? If so I can log this internally so we can track interest over time.

[bteh]

Hey @dataders , my team and I are also facing this same exact issue. We were planning to data shares to get our production tables into a lower environment, but it comes in as a separate database. Whenever I look at dbt logs, I see that it queries information_schema."columns" which doesn't return those data-shared (separate database) tables. However, when I query svv_redshift_columns, we see those production tables (datashared) in this table.

This would help us tremendously and is a huge blocker for us to get our lower environment setup.

[dlassanske-daxko]

@bteh the solution for Redshift that I came up with in the meantime is to create a macro like this:

{% macro get_redshift_columns(database, schema, table) %}
  {% set columns = [] %}
  {% if execute %}
    {% set columns = run_query("SHOW COLUMNS FROM TABLE "~database~"."~schema~"."~table) %}
  {% endif %}
  {% do return(columns) %}
{% endmacro %}

and then call it in your model.

[gmatheou366]

It seems that this issue also affects codegen's generate_source command (https://github.com/dbt-labs/dbt-codegen/blob/0.12.1/macros/generate_source.sql)