I'm not sure that looks like a safe patch. Synchronization does more than help prevent races... it also introduces memory barriers. Removing synchronization to objects that can change is very tricky business (witness the double-checked locking antipattern).
-Yonik Now hiring -- http://tinyurl.com/7m67g On 10/11/05, Chris Lamprecht <[EMAIL PROTECTED]> wrote: > > Hi Peter, > > I observed the same issue on a multiprocessor machine. I included a > small fix for this in the NIO patch (against the 1.9 trunk) here: > http://issues.apache.org/jira/browse/LUCENE-414#action_12322523 > > The change amounts to the following methods in SegmentReader.java, to > remove the need synchronized() block by taking a "snapshot" of the > variable: > > // Removed synchronized from document(int) > public Document document(int n) throws IOException { > if (isDeleted(n)) > throw new IllegalArgumentException > ("attempt to access a deleted document"); > return fieldsReader.doc(n); > } > > // removed synchronized from isDeleted(int) > public boolean isDeleted(int n) { > // avoid race condition by getting a snapshot reference > final BitVector snapshot = deletedDocs; > return (snapshot != null && snapshot.get(n)); > } > > We've been using this in production for a while and it fixed the > extremely slow searches when there are deleted documents. Maybe it > could be applied to the trunk, independent of the full NIO patch. > > -chris > >
