Updating

Updating OpenGrok from one version to another is usually easy:

• extract the distribution archive
• deploy the new web application

However, in case the index format changed, it is necessary to reindex from scratch, i.e. delete all files under data root and indexing anew. Since reindexing from scratch is usually costly procedure (both time and resource wise), for most production deployments it should be done in the background, to a dedicated data root (to avoid overwriting existing data), using a snapshot of the source root (to avoid indexing data in flux). Once it is over, the data root can be switched (e.g. by renaming the directories) and the new web application deployed. Since the web application has a dependency on concrete format of the index, it is necessary to switch it only in the last step.