Tycho downloads p2.indexes on every build

Question

I'm building an RCP and several other plug-ins with Maven & Tycho. This works very fine, unless one issue:

On every(!) build, Tycho loads all needed eclipse librarys, even when the where already downloaded 10 seconds ago. Aren't they saved automatically in the local repository, or am I missing some configuration? all p2.indexes. But this is also annoying. Can I turn this off, so that it'll only check once a week?

  <properties>
    <tycho-version>0.15.0</tycho-version>
  </properties>

  <repositories>
   <repository>
      <id>eclipse-indigo</id>
      <layout>p2</layout>
      <url>http://download.eclipse.org/releases/indigo</url>
   </repository>
  </repositories>

  <build>
    <plugins>
      <plugin>
        <groupId>org.eclipse.tycho</groupId>
        <artifactId>tycho-maven-plugin</artifactId>
        <version>${tycho-version}</version>
        <extensions>true</extensions>
      </plugin>
    </plugins>
  </build>

Answer 1

p2 artifacts as well as metadata files like content.jar and artifacts.jar are cached. p2 will do a timestamp comparison check only on each build (using HTTP HEAD) to check if the local cache is outdated.

If you want to avoid this, use maven offline mode (CLI option --offline)