I would like to share my experience for upgrading from Lucene 1.9 to Lucene 2.2, build 515893.
I have been working on a product called DBSight. It has both a designing web UI for configuring database crawl, and also capabilities to serve search requests like later-emerged SOLR. So DBSight can do both indexing and searching. Previously I have upgraded to 1.3, 1.4, and 1.9, all were pretty easy and went through well. Upgrading to 2.2 isn't so straight forward though. Last time when Lucene 2.0 came out, I tried it by simply dropping lucene-2.0.jar onto the classpath. The indexing went well, but somehow the searching didn't work any more, no results and without any exceptions! That's wierd and I have to back off. Now with Lucene 2.2, I tried it again. This time, there are a bunch of NullPointerException when starting DBSight. But at least I can fix those. So I take some time to write down anything that may need to change. Your code may differ depending on which API you use. 1. Use document.getFields() instead of deprecated document.fields() This is an easy one, but with some code change. The return type changed from Enumeration to List. So you may need to write 2~3 lines of code. The upgrading should be easy and not even need a QA(really?). 2. Use FSDirectory.getDirectory(file) instead of FSDirectory.getDirectory(file, isCreating) FSDirectory.getDirectory(file) will not automatically create directory any more. I missed this deprecated yet convenient parameter. However, not so bad. 3. RAMDirectory related changes It took me something to find this out. Previously, after ramDirectory = new RAMDirectory(file) I could ramDirectory.close() to release the resources. And later, I could do a check for IndexReader.indexExists(ramDirectory) to see if there is an index in the directory. FSDirectory behaves this way also. But with lucene 2.2, NullPointerExceptions came out. It turns out when ramDirectory.close(), the instance variable fileMap is set to null. And IndexReader.indexExists(ramDirectory) is reading fileMap to look for indexes, causing the NPE. 4. clearing remaining locks from last indexing In order to clear indexing locks, previously I manually cleared write lock and commit lock. As pointed out by others, the commit lock now is gone. And the unlocking logic is already wrapped in IndexReader.unlock(directory), I should use that directly. In general, the upgrade is smooth, and I can compile Lucene in JDK 1.4 without any problem. Now I can try out the new optimizations and features, especially on merging, and test out whether the query performance improves or not. This feature sounds interesting: indexWriter.addIndexesNoOptimize(directories), but the result is, no obvious speedup, and the worst part: the dreaded "java.io.IOException: read past EOF". Guess I will skip this feature for now. -- Chris Lu ------------------------- Instant Full-Text Search On Any Database/Application site: http://www.dbsight.net demo: http://search.dbsight.com --------------------------------------------------------------------- To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
