[LUCENE-769] [PATCH] Performance improvement for some cases of sorted search

• Type: Improvement
• Status: Closed
• Priority: Major
• Resolution: Won't Fix
• Affects Version/s: 2.0.0
• Component/s: core/search
• Lucene Fields: New, Patch Available
• Assignee: Unassigned
• Reporter: Artem Vasiliev
• Created: 09/Jan/07 22:26
• Updated: 28/Aug/22 11:33
• Resolved: 10/Mar/13 13:17

Description

It's a small addition to Lucene that significantly lowers memory consumption and improves performance for sorted searches with frequent index updates and relatively big indexes (>1mln docs) scenario. This solution supports only single-field sorting currently (which seem to be quite popular use case). Multiple fields support can be added without much trouble.

The solution is this: documents from the sorting set (instead of given field's values from the whole index - current FieldCache approach) are cached in a WeakHashMap so the cached items are candidates for GC. Their fields values are then fetched from the cache and compared while sorting.