From Eclipsepedia

PDOM & Indexing

This section describes the design for the new indexing architecture in CDT 3.1. It essentially revolves around a new database for indexing information, the PDOM, which stores binding and name elements as they would appear in the DOM. Thus the term Persisted DOM, PDOM. Since DOM information is being stored in the index, we can now use it for more things as well as use it to speed up indexing.

• History
• Overview
• PDOM Lifecycle