[LUCENE-2010] Remove segments with all documents deleted in commit/flush/close of IndexWriter instead of waiting until a merge occurs.

• Type: Improvement
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 2.9
• Fix Version/s: 3.1, 4.0-ALPHA
• Component/s: core/index
• Lucene Fields: New
• Assignee: Michael McCandless
• Reporter: Uwe Schindler
• Created: 26/Oct/09 10:11
• Updated: 28/Aug/22 12:12
• Resolved: 26/Jan/11 21:56

Description

I do not know if this is a bug in 2.9.0, but it seems that segments with all documents deleted are not automatically removed:

4 of 14: name=_dlo docCount=5
  compound=true
  hasProx=true
  numFiles=2
  size (MB)=0.059
  diagnostics = {java.version=1.5.0_21, lucene.version=2.9.0 817268P - 2009-09-21 10:25:09, os=SunOS,
     os.arch=amd64, java.vendor=Sun Microsystems Inc., os.version=5.10, source=flush}
  has deletions [delFileName=_dlo_1.del]
  test: open reader.........OK [5 deleted docs]
  test: fields..............OK [136 fields]
  test: field norms.........OK [136 fields]
  test: terms, freq, prox...OK [1698 terms; 4236 terms/docs pairs; 0 tokens]
  test: stored fields.......OK [0 total field count; avg ? fields per doc]
  test: term vectors........OK [0 total vector count; avg ? term/freq vector fields per doc]

Shouldn't such segments not be removed automatically during the next commit/close of IndexWriter?

Mike McCandless:
Lucene doesn't actually short-circuit this case, ie, if every single doc in a given segment has been deleted, it will still merge it [away] like normal, rather than simply dropping it immediately from the index, which I agree would be a simple optimization. Can you open a new issue? I would think IW can drop such a segment immediately (ie not wait for a merge or optimize) on flushing new deletes.

Issue Links

• relates to: LUCENE-1960 Remove deprecated Field.Store.COMPRESS