# Managing project history

One of the most powerful features of SonarQube is that it shows you not just your project health today, but how it has changed over time. It does that by selectively keeping data from previous analyses (see [housekeeping](https://docs.sonarsource.com/sonarqube-server/10.1/instance-administration/housekeeping "mention")). It doesn’t keep all previous analyses. That would bloat the database. Similarly, for the analyses it does keep, SonarQube doesn’t keep all the data. Once a project snapshot moves from being the "last analysis" (i.e., the most recent) to being part of the project’s history, data below the project level is purged to keep from bloating the database.

Typically these aren’t things you need to even think about. SonarQube just handles them for you. But occasionally you may need to remove a bad snapshot from a project’s history or change the housekeeping algorithms.

## Managing history <a href="#managing-history" id="managing-history"></a>

Occasionally, you may need to manually delete a project snapshot, whether because the wrong quality profile was used, or because there was a problem with analysis, and so on. Note that the most recent snapshot (labeled **Last snapshot**) can never be deleted.

{% hint style="info" %}
**About deleting snapshots**

Deleting a snapshot is a 2-step process:

* The snapshot must first be removed from the project history by clicking on Delete snapshot. It won’t be displayed anymore on this History page but will still be present in the database.
* The snapshot is actually deleted during the next project analysis.
  {% endhint %}

At the project level, from the front page **Activity** list, choose **Show More** to see the full activity list.

For every snapshot, it is possible to manually:

* Add, rename or remove a version.
* Add, rename or remove an event.
* Delete the snapshot.


---

# Agent Instructions: Querying This Documentation

If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter:

```
GET https://docs.sonarsource.com/sonarqube-server/10.1/project-administration/managing-project-history.md?ask=<question>
```

The question should be specific, self-contained, and written in natural language.
The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.