I'm using the latest MonetDB5: MonetDB-Nov2009-SuperBall-SP1 on Red Hat Enterprise Linux AS release 4 (Nahant Update 4) x86_64. dependencies: openssl-0.9.8l, pcre-8.00. The box has 8G physical memory, about half of them is available. building options: ./monetdb-install.sh --prefix=/opt/monetdb5 --enable-sql --enable-optimise After installation, I started the mserver5 process: /opt/monetdb5/bin/mserver5 --dbinit "include sql;", then I load one table exported from MySQL with about 1M rows and 20 columns. I noticed small memory increase when I run a simple query on the mclient console for some times. So I run this query through the JDBC interface for 10000, I can see a big memory consumption rise when the test program is running. and finally the mserver5 process crashed with segmentation fault. I can always reproduce this problem. What's wrong? Have I used some wrong build options? Help! Frank