[LUCENE-758] IndexReader.isCurrent fails when using two IndexReaders

• Type: Bug
• Status: Resolved
• Priority: Minor
• Resolution: Invalid
• Affects Version/s: 2.1

Environment

Operating System: other
Platform: other

• Lucene Fields: New
• Assignee: Unassigned
• Reporter: Bernhard Messer
• Created: 22/Dec/06 12:40
• Updated: 28/Aug/22 11:33
• Resolved: 01/Jan/07 13:49

Description

there is a problem in IndexReader.isCurrent() if using two reader instances where one of them is based on a RAMDirectory. If there is an index and we open two IndexReaders where one is based on a FSDirectory and the other is based on a RAMDirectory, the IndexReader using the RAMDirectory does not recognize when the underlaying index has changed. The method IndexReader.isCurrent() always returns true. The testcase below shows the problem.

I did not find an ideal solution to solve the problem. I think the best way would be to change the IndexReader.isCurrent() implementation from:
public boolean isCurrent() throws IOException

{ return SegmentInfos.readCurrentVersion(directory) == segmentInfos.getVersion(); }

to something like:
public boolean isCurrent() throws IOException

{ return directory.readCurrentVersion() == segmentInfos.getVersion(); }

As far as i can see this would work for FS- and RAMDirectory. But then the implementing Directory classes have to know about "segment" files and there formating details.
What do others think ?

/**

• additional testcase for IndexReaderTest to show the problem when using two different Readers
  */
  public void testIsCurrentWithCombined() throws Exception { String tempDir = System.getProperty("tempDir"); if (tempDir == null) throw new IOException("tempDir undefined, cannot run test"); File indexDir = new File(tempDir, "lucenetestiscurrent"); Directory fsStore = FSDirectory.getDirectory(indexDir, true); IndexWriter writer = new IndexWriter(fsStore, new SimpleAnalyzer(), true); addDocumentWithFields(writer); writer.close(); IndexReader reader1 = IndexReader.open(fsStore); IndexReader reader2 = IndexReader.open(new RAMDirectory(fsStore)); assertTrue(reader1.isCurrent()); assertTrue(reader2.isCurrent()); reader1.deleteDocument(0); reader1.close(); // BUG: reader based on the RAMDirectory does not recognize the index change. assertFalse(reader2.isCurrent()); reader2.close(); }