Sharding the indexes by project

Problem Definition

Currently the Lucene index is the same for whole JIRA index and for large JIRA instances it can be quite large also. Eg: around 20Gb. To run search Lucene need to access whole index.

Suggested Solution

Sharding the indexes by project, which would give the ability to do things like reindex just that one project without issues from other projects being involved in the segment merge activity. Similarly, searches that are limited to a single project would have a much smaller index to work with more naturally this way.

Notest

See topic for more details: https://answers.atlassian.com/questions/10416064/what-is-the-difference-between-a-system-level-and-project-level-reindex