Dbt Test --store-failures Creates *audit DB On One Node

Aug 12, 2025 by Rajiv Sharma 56 views

dbt Test with ClickHouse: Troubleshooting *audit DB Creation on One Node

Introduction

Hey guys! Ever run into a situation where your dbt tests, specifically when using the --store-failures flag, only create the *audit database on a single node in your ClickHouse cluster? It's a real head-scratcher, especially when you've got your cluster configuration nicely set up in your dbt profiles. This article dives deep into this issue, exploring the bug, how to reproduce it, expected behavior, and even provides code examples to help you understand and troubleshoot. We'll also cover the configurations used and the ClickHouse server environment. So, let's get started and figure out why this is happening and how to fix it!

The Bug: *audit DB Created on One Node Only

The core issue here is that when you run dbt test --store-failures, the *audit database should ideally be created across all nodes in your ClickHouse cluster, especially if you've specified the cluster configuration in your dbt profiles. However, the bug causes the database to be created on only one node, which can lead to inconsistencies and other issues in a distributed environment. This defeats the purpose of having a cluster in the first place, right? Imagine running tests and then not having the audit logs uniformly available across your nodes – that’s a debugging nightmare!

This behavior contradicts the expected outcome, where the cluster configuration should ensure that any database operations, including the creation of the *audit database, are propagated across all nodes in the cluster. This discrepancy can stem from how dbt interacts with ClickHouse when the --store-failures flag is used, possibly overlooking the cluster settings during the database creation process. Understanding this is crucial for maintaining data integrity and consistency in your ClickHouse cluster. We want all our nodes singing from the same hymn sheet, don't we?

To make sure we're all on the same page, it's worth emphasizing why the *audit database is so important. It's where dbt stores information about test failures when you use the --store-failures flag. This allows you to track and analyze test results over time, which is super useful for identifying patterns and recurring issues. But if this database isn't consistently available across your cluster, you're missing out on a big piece of the puzzle. So, let's get this sorted!

Steps to Reproduce the Bug

Okay, so how do you actually see this bug in action? Let's break it down into simple steps. This way, you can try it out yourself and confirm if you're experiencing the same issue. Reproducing the bug is the first step in fixing it, as it gives you a clear understanding of the problem's context.

Create a dbt profile with the cluster config:

First things first, you need to set up your dbt profile with the ClickHouse cluster configuration. This involves specifying the cluster name in your profiles.yml file. This tells dbt that you're working with a ClickHouse cluster and that it should distribute operations across the nodes. Think of this as setting the stage for the bug to appear. Without the cluster config, dbt won't even know it's supposed to be creating the database across multiple nodes.
Run dbt test --store-failures:

Next, you'll run the dbt test --store-failures command, making sure you're using the profile you just configured. The --store-failures flag is key here, as it's what triggers the creation of the *audit database. This command tells dbt to run your tests and, if any fail, store the details in the audit database. It's like telling dbt, "Hey, pay attention to these failures and keep a record of them."
Inspect your ClickHouse cluster:

After running the tests, you'll need to dive into your ClickHouse cluster and check if the *audit database has been created on all nodes. This is where you'll see the bug in action. You might find that the database only exists on one node, which is not what we want. This step is crucial for confirming that the bug is indeed present and for understanding its scope. It's like the detective work of debugging – you're looking for clues!

By following these steps, you can reliably reproduce the bug and see firsthand how it affects your ClickHouse setup. This hands-on approach is super valuable for understanding the problem and coming up with a solution. Now, let's talk about what should actually happen.

Expected Behavior

So, what's the ideal scenario here? What should happen when you run dbt test --store-failures with a cluster config in your dbt profile? Well, the expectation is pretty straightforward: the *audit database should be created on all nodes in your ClickHouse cluster. This ensures that the test failure information is consistently available across your entire cluster.

When the cluster configuration is correctly specified in your dbt profile, dbt should recognize that it's working with a distributed environment. This means that any database operations, including the creation of the *audit database, should be propagated to all nodes in the cluster. This is crucial for maintaining data integrity and consistency, especially in a production environment where you might have multiple nodes handling different parts of your data pipeline. Think of it as a synchronized dance – all the nodes need to be in step!

The reason this is so important is that if the *audit database only exists on one node, you're going to run into problems when trying to query or analyze test failures. You might only see a partial view of the failures, or you might have to jump through hoops to access the data from the node where the database was created. This adds unnecessary complexity and can slow down your debugging process. We want a smooth, seamless experience, right?

In a properly configured ClickHouse cluster, data is often distributed across multiple nodes for performance and resilience. If the *audit database is only on one node, it creates a single point of failure and a potential bottleneck. By ensuring the database is replicated across all nodes, you're not only improving consistency but also enhancing the reliability of your testing infrastructure. It's like having a backup plan – you're prepared for anything!

Code Examples: Models or Profile Settings

Let's get our hands dirty with some code! Here’s an example of a dbt profile that includes the cluster configuration. This is the kind of setup you'd expect to work correctly, but as we've seen, sometimes things don't go as planned. Understanding the code is key to figuring out where things might be going wrong.

data_platform_clickhouse_dbt:
  target: prod_raw
  outputs:
    prod_raw:
      type: clickhouse
      schema: "{{ 'prod_metrics_' + var('pr_id') if var('pr_id', '') != '' else 'prod_metrics' }}"  # Append 'metrics_' only if 'pr_id' is set
      host: demo-host
      port: 8443
      user: USER
      password: PWD
      secure: true
      verify: false
      cluster: '{cluster}'

In this profile, you can see that we've specified the cluster setting. This is the crucial part that tells dbt to consider the ClickHouse cluster when performing operations. The schema setting is also worth noting, as it uses a variable pr_id to dynamically set the schema name. This is a common pattern in dbt for creating environments for pull requests or other development contexts.

Now, let's look at the command you'd typically run to trigger the bug:

dbt test --profiles-dir=./profiles/prod --vars "{'pr_id': '${{ env.PR_ID }}'}"  --store-failures --select state:modified --state ./state --defer

This command does a few things. It specifies the profiles directory, sets a variable for the pull request ID (if applicable), uses the --store-failures flag to store test failures, selects tests based on their state, and defers to a previous state. It's a pretty comprehensive command that covers a lot of ground in a typical dbt workflow.

By examining these code examples, we can start to narrow down where the problem might lie. Is it in the profile configuration? Is it in the way dbt interprets the cluster setting? Or is it something else entirely? Let's keep digging!

Configuration Details

To really get to the bottom of this, we need to look at the configuration details of the environment where this bug is occurring. This includes the dbt-related packages and the ClickHouse server version. Knowing these details helps us understand if the bug is specific to certain versions or configurations.

Environment

Here's a rundown of the dbt-related packages being used:

+ dbt-adapters==1.16.3
+ dbt-common==1.27.1
+ dbt-core==1.10.7
+ dbt-extractor==0.6.0
+ dbt-protos==1.0.348
+ dbt-semantic-interfaces==0.9.0
+ clickhouse-driver==0.2.9
+ dbt-clickhouse==1.8.9
+ dbt-core==1.8.9

These versions give us a snapshot of the dbt ecosystem in use. It's worth noting that there are a couple of different versions of dbt-core listed (1.10.7 and 1.8.9), which might indicate a potential conflict or an environment with multiple dbt installations. This could be a red herring, but it's something to keep in mind.

ClickHouse Server

ClickHouse Server version: 25.5.7

The ClickHouse server version is also crucial. Different versions of ClickHouse might have different behaviors or bug fixes that could affect how dbt interacts with the database. Knowing the exact version helps us search for known issues or compatibility problems.

With these configuration details in hand, we can start to form a clearer picture of the environment where the bug is happening. This information is invaluable for troubleshooting and finding a solution. It's like having the full ingredients list for a recipe – you need to know everything that's going in to understand why it's not turning out right!

Conclusion

So, we've taken a deep dive into the issue of dbt tests only creating the *audit database on one node in a ClickHouse cluster when using the --store-failures flag. We've covered the bug, how to reproduce it, the expected behavior, code examples, and configuration details. Hopefully, this has given you a solid understanding of the problem and the context in which it occurs.

By understanding the bug and its context, you're better equipped to troubleshoot and find a solution. Whether it's a configuration issue, a version incompatibility, or a bug in dbt-clickhouse, having a clear understanding of the problem is half the battle. Keep experimenting, keep digging, and you'll get there! And remember, you're not alone in this – the dbt and ClickHouse communities are full of folks who are happy to help. Happy debugging, and may your *audit databases be consistently created across all your nodes!