Introduction

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. 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 the "Last analysis" (i.e. the most recent) to being part of the project's history, data below the project level is purged - again 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. 

Events

There are four types of events:

• Quality Gate - the status of the quality gate changed.
• Profile - the quality profile used to analyze the project changed - either the profile was edited, or a different profile was used to analyze the project.
• Version - the project's version changed.
• Other - an event was manually created on a snapshot. See Managing History, below.

Events are shown on the project front page and in the project Activity page. 

Managing History

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.

At 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