[LUCENE-2809] IndexWriter.numDocs doesn't take into account applied but not flushed deletes

• Type: Bug
• Status: Closed
• Priority: Minor
• Resolution: Fixed
• Fix Version/s: 3.1, 4.0-ALPHA
• Component/s: core/index
• Lucene Fields: New
• Assignee: Michael McCandless
• Reporter: Michael McCandless
• Created: 10/Dec/10 13:52
• Updated: 28/Aug/22 12:37
• Resolved: 23/Jan/11 13:37

Description

The javadoc states that buffered deletes are not taken into account and so you must call commit first.

But, if you do that, and you're using CMS, and you're unlucky enough to have a background merge commit just after you call commit but before you call .numDocs, you can still get a wrong count back.

The fix is trivial – numDocs should also consult any pooled readers for their current del count.

This is causing an intermittent failure in the new TestNRTThreads.