Yea, I noticed that ;). Even so, I think that with NRT, even the lower level
readers are cloned, meaning that you always get a new instance... . Here is
a sample program that tests this behavior, am I doing something wrong? By
the way, if what I say is correct, it affects field cache as well....
public static void main(String[] args) throws Exception {
Directory dir = new RAMDirectory();
IndexWriter indexWriter = new IndexWriter(dir, new
StandardAnalyzer(Version.LUCENE_CURRENT), true,
IndexWriter.MaxFieldLength.UNLIMITED);
IndexReader reader = indexWriter.getReader();
Set<IndexReader> readers = new HashSet<IndexReader>(); // tracks all
readers
for (int i = 0; i < 100; i++) {
readers.add(reader);
Document doc = new Document();
doc.add(new Field("id", Integer.toString(i), Field.Store.YES,
Field.Index.NO));
indexWriter.addDocument(doc);
IndexReader newReader = reader.reopen(true);
if (reader == newReader) {
System.err.println("Should not get the same reader...");
} else {
reader.close();
reader = newReader;
}
}
reader.close();
// now, go and check that all are ref == 0
// and, that all readers, even sub readers, are unique instances
(sadly...)
Set<IndexReader> allReaders = new HashSet<IndexReader>();
for (IndexReader reader1 : readers) {
if (reader1.getRefCount() != 0) {
System.err.println("A reader is not closed");
}
if (allReaders.contains(reader1)) {
System.err.println("Found an existing reader...");
}
allReaders.add(reader1);
if (reader1.getSequentialSubReaders() != null) {
for (IndexReader reader2 : reader1.getSequentialSubReaders()) {
if (reader2.getRefCount() != 0) {
System.err.println("A reader is not closed...");
}
if (allReaders.contains(reader2)) {
System.err.println("Found an existing reader...");
}
allReaders.add(reader2);
// there should not be additional readers...
if (reader2.getSequentialSubReaders() != null) {
System.err.println("Should not be more readers...");
}
}
}
}
indexWriter.close();
}
On Tue, May 18, 2010 at 12:30 AM, Yonik Seeley
<[email protected]>wrote:
> On Mon, May 17, 2010 at 5:00 PM, Shay Banon <[email protected]> wrote:
> > I wanted to verify if my understanding is correct. Assuming that I use
> > NRT, and refresh, say, every 1 second, caching based on IndexReader, such
> is
> > what is used in the CachingWrapperFilter is basically useless
>
> No, it's fine. Searching in Lucene is now done per-segment, and so
> the readers that are passed to Filter.getDocIdSet are the segment
> readers, not the top-level readers. Caching is now per-segment.
>
> -Yonik
> http://www.lucidimagination.com
>
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