Ahhh, OK. In 2.3, when you open IndexWriter with autoCommit=false,
the only way to make changes visible is to close the writer. Can you
just open with autoCommit=true? Then flush() makes changes visible.
You can increase the flushing criteria to absurdly large values so
the writer never flushes on its own, if that's necessary.
In 2.4, even when autoCommit=false, you can make changes visible
(and, durable to power outage or OS/machine crash) by calling commit
(). But remember 2.4 is trunk so "use at your own risk"!
Both flush() and commit() are rather costly operations, so calling
them too frequently will hurt your indexing throughput.
Mike
[EMAIL PROTECTED] wrote:
I used the new released 2.3 and set autoCommit=false.
Sorry my code to create the IndexWriter is like this:
Directory dir = FSDirectory.getDirectory(INDEX_DIR);
IndexWriter writer = new IndexWriter(dir, false, new
StandardAnalyzer(), true);
writer.setTermIndexInterval(8);
writer.setMaxBufferedDocs(3);
writer.setMergeFactor(3);
I just would like to control the flush of the segments by myself.
But in the released 2.3, there is no interface for users to flush
the segments by themselves, right?
If I would like to achieve this, do you mean I have to use the 2.4
version instead of 2.3?
Thank you
Yours
Liu Chao
-----Original Message-----
From: Michael McCandless [mailto:[EMAIL PROTECTED]
Sent: 2008年3月25日 17:21
To: java-dev@lucene.apache.org
Subject: Re: IndexWriter.flush dose not flush the segmentInfos in
Lucene 2.3
Do you mean 2.4 (trunk) not 2.3? In 2.4, flush has been deprecated.
Instead, you should use commit() to force the changes to be visible
to a reader.
On 2.3 I believe this works correctly as long as the write is opened
with autoCommit=true (which your example below is).
Mike
[EMAIL PROTECTED] wrote:
I found that for lucene 2.3, IndexWriter.flush does not flush the
segmentInfos.
For example, I create a new index directory and add 10 documents to
it:
IndexWriter writer = new IndexWriter(dir, new StandardAnalyzer(),
true);
indexDocs(writer, SOURCE_DIR);//in the source directory, there are
10 documents.
writer.flush();
If the IndexWriter is not closed and then an IndexReader is opened
to this index:
IndexReader reader = IndexReader.open(INDEX_DIR);
int docNum = reader.numDocs();//docNum = 0
at this time, docNum = 0, the new opened IndexReader cannot see the
new added documents.
But if the IndexWriter is closed and then an IndexReader is opened
to the Index:
writer.close();
IndexReader reader = IndexReader.open(index);
int docNum = reader.numDocs();//docNum = 10
at this time the new opened IndexReader can see the documents added
by the IndexWriter.
I think the reason is :
IndexWriter.flush only flushes the data from memory to disk, the
metadata of segments segmentInfos is not flushed to the disk.
So that if the IndexWriter is not closed, the new opened
IndexReader cannot see the new added documents.
That means what the IndexReader can see is not the segment
structure when it is opened but when the last time the IndexWriter
is opened.
I think it is a bug for new version of lucene 2.3 or at least the
behavior is different from lucene 2.1
Yours
Liu Chao
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