We have a batch job that updates 10,000 preexisting User entities in a single transaction; each User has an @IndexedEmbedded UserDetails entity which is also updated during the job run. When run with hibernate.search.worker.execution=sync, life is good.
When we run with async, indexing intermittently fails with a Lucene AlreadyClosedException. There is no other exception logged even with TRACE logging enabled.
We did not see this issue with 3.1.1GA but Sanne has noted that it is possible the exceptions were occurring and were not being logged in that version; I cannot exclude this possibility.
Posted a log file to http://www.attensa.com/download/files/attensa.log the first exception is at timestamp [2010-04-21 11:23:45.992,236829]
Associated forum discussion here: https://forum.hibernate.org/viewtopic.php?f=9&t=1004022&p=2429214#p2429214