> For the complete documentation index, see [llms.txt](https://documentation.immuta.com/latest/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://documentation.immuta.com/latest/configuration/integrations/databricks/databricks-spark/how-to-guides/project-udfs.md).

# Project UDFs Cache Settings

Lower the web service cache timeout settings of project UDFs

This page outlines the configuration for setting up project UDFs, which allow users to set their current project in Immuta through Spark. For details about the specific functions available and how to use them, see the [Use Project UDFs (Databricks) page](/latest/governance/author-policies-for-data-access-control/projects-and-purpose-based-access-control/writing-to-projects/reference-guides/project-udfs.md).

{% hint style="info" %}
**Use project UDFs in Databricks Spark**

Currently, caches are not all invalidated outside of Databricks because Immuta caches information pertaining to a user's current project. Consequently, this feature should only be used in Databricks.
{% endhint %}

1. Lower the web service cache timeout in Immuta:
   1. Click the <i class="fa-gear">:gear:</i> **App Settings** icon and scroll to the **HDFS Cache Settings** section.
   2. Lower the **Cache TTL of HDFS user names (ms)** to **0**.
   3. Click **Save**.
2. Raise the cache timeout on your Databricks cluster: In the Spark environment variables section, set the `IMMUTA_CURRENT_PROJECT_CACHE_TIMEOUT_SECONDS` and `IMMUTA_PROJECT_CACHE_TIMEOUT_SECONDS` to high values (like `10000`).

   *Note: These caches will be invalidated on cluster when a user calls `immuta.set_current_project`, so they can effectively be cached permanently on cluster to avoid periodically reaching out to the web service.*


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