[LUCENE-2529] always apply position increment gap between values

• Type: Bug
• Status: Closed
• Priority: Minor
• Resolution: Fixed
• Affects Version/s: 2.9.3, 3.0.2, 3.1, 4.0-ALPHA
• Fix Version/s: 3.1, 4.0-ALPHA
• Component/s: core/index

Environment

(I don't know which version to say this affects since it's some quasi trunk release and the new versioning scheme confuses me.)

• Lucene Fields: New, Patch Available
• Assignee: Koji Sekiguchi
• Reporter: David Smiley
• Created: 06/Jul/10 16:30
• Updated: 28/Aug/22 12:28
• Resolved: 28/Sep/10 02:21

Description

I'm doing some fancy stuff with span queries that is very sensitive to term positions. I discovered that the position increment gap on indexing is only applied between values when there are existing terms indexed for the document. I suspect this logic wasn't deliberate, it's just how its always been for no particular reason. I think it should always apply the gap between fields. Reference DocInverterPerField.java line 82:

if (fieldState.length > 0)
fieldState.position += docState.analyzer.getPositionIncrementGap(fieldInfo.name);

This is checking fieldState.length. I think the condition should simply be: if (i > 0).
I don't think this change will affect anyone at all but it will certainly help me. Presently, I can either change this line in Lucene, or I can put in a hack so that the first value for the document is some dummy value which is wasteful.

Issue Links

• relates to: LUCENE-2668 offset gap should be added regardless of existence of tokens in DocInverterPerField