Hi, I implemented a mechanism which I mentioned in thread http://forum.compass-project.org/thread.jspa?threadID=215559&tstart=15 It increased insertion performance approximately 10 times and it is fine for us. However, I inserted approximately 400000 objects into compass indexes. And After this insertion I performed a query and took the following exception Caused by: java.lang.UnsupportedOperationException at org.compass.core.lucene.engine.transaction.readcommitted.BitSetByAliasFilter$Al lSetBitSet.and(BitSetByAliasFilter.java:120) at org.compass.core.lucene.util.ChainedFilter.doChain(ChainedFilter.java:195) at org.compass.core.lucene.util.ChainedFilter.bits(ChainedFilter.java:143) at org.compass.core.lucene.util.ChainedFilter.bits(ChainedFilter.java:112) at org.apache.lucene.search.IndexSearcher.search(IndexSearcher.java:133) at org.apache.lucene.search.IndexSearcher.search(IndexSearcher.java:113) at org.apache.lucene.search.MultiSearcher.search(MultiSearcher.java:204) at org.apache.lucene.search.Hits.getMoreDocs(Hits.java:100) at org.apache.lucene.search.Hits.<init>(Hits.java:77) at org.apache.lucene.search.Searcher.search(Searcher.java:64) at org.compass.core.lucene.engine.transaction.AbstractTransaction.findByQuery(Abst ractTransaction.java:207) at org.compass.core.lucene.engine.transaction.readcommitted.ReadCommittedTransacti on.doFind(ReadCommittedTransaction.java:205) at org.compass.core.lucene.engine.transaction.AbstractTransaction.find(AbstractTra nsaction.java:103) at org.compass.core.lucene.engine.LuceneSearchEngine.find(LuceneSearchEngine.java: 351) at org.compass.core.lucene.engine.LuceneSearchEngineQuery.hits(LuceneSearchEngineQ uery.java:189) at org.compass.core.impl.DefaultCompassQuery.hits(DefaultCompassQuery.java:158)