[LUCENE-8941] Build wildcard matches more lazily

• Type: Improvement
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 8.3
• Lucene Fields: New
• Assignee: Alan Woodward
• Reporter: Alan Woodward
• Created: 30/Jul/19 10:50
• Updated: 28/Aug/22 15:49
• Resolved: 07/Aug/19 11:00

Description

When retrieving a Matches object from a multi-term query, such as an AutomatonQuery or TermInSetQuery, we currently find all matching term iterators up-front, to return a disjunction over all of them. This can be inefficient if we're only interested in finding out if anything matched, and are iterating over a different field to retrieve offsets.

We can improve this by returning immediately when the first matching term is found, and only collecting other matching terms when we start iterating.