Slim CI with state comparison in dbt - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ Predict Output

intermediate

Output of dbt slim CI with state comparison command

What is the output of the following dbt command when using slim CI with state comparison?

dbt build --state path/to/previous_run --select state:modified

Assume the previous run had models A, B, and C, and only model B was modified.

dbt

dbt build --state path/to/previous_run --select state:modified

A Builds only model B and its dependencies.

B Builds all models A, B, and C regardless of changes.

C Builds only models A and C, skipping B.

D Builds no models because state comparison disables builds.

💡 Hint

Think about what 'state:modified' selects in dbt.

The --select state:modified flag tells dbt to build only models that have changed since the last run, plus their dependencies. Since only model B was modified, only B and its dependencies are built.

❓ data_output

intermediate

Number of models built with slim CI and state comparison

Given a dbt project with 10 models where 3 models were modified since the last run, how many models will be built using:

dbt build --state path/to/previous_run --select state:modified

Assuming no dependencies outside these 3 models.

dbt

dbt build --state path/to/previous_run --select state:modified

A 10 models

B 3 models

C 0 models

D Depends on the number of dependencies of the modified models

💡 Hint

Consider if dependencies affect the count here.

Since the 3 modified models have no dependencies, only those 3 models are built.

🔧 Debug

advanced

Identify the error in slim CI state comparison usage

What error will occur when running this command?

dbt build --state path/to/previous_run --select state:modified+ --exclude state:modified

dbt

dbt build --state path/to/previous_run --select state:modified+ --exclude state:modified

A Error: Missing required --target flag.

B No error, builds all models.

C Error: Conflicting selection and exclusion of the same state selector.

D Warning: Ignoring --exclude flag.

💡 Hint

Think about what happens when you select and exclude the same models.

The command tries to select models modified and their children, but excludes the modified models themselves, causing a conflict in selection logic.

🚀 Application

advanced

Applying slim CI with state comparison in a CI pipeline

You want to optimize your CI pipeline to only run tests on changed models and their dependencies. Which dbt command should you use?

A dbt test --state path/to/previous_run --exclude state:modified+

B dbt test --select state:modified

C dbt test --exclude state:modified

D dbt test --state path/to/previous_run --select state:modified+

💡 Hint

Consider how to include dependencies of modified models.

The state:modified+ selector includes modified models and their children, ensuring tests run on all affected models.

🧠 Conceptual

expert

Understanding limitations of slim CI with state comparison

Which of the following is a limitation of using slim CI with state comparison in dbt?

A It may miss models affected by indirect dependency changes if state files are outdated.

B It always rebuilds the entire project regardless of changes.

C It cannot be used with incremental models.

D It requires manual specification of changed models.

💡 Hint

Think about how state files affect detection of changes.

If the state files are not up to date, indirect changes in dependencies might not be detected, causing some models to be skipped.