Hi, How many files MonetDb is keeping open during runtime? I have running some test on MonetDb on RedHat 6 environment and faced the problem with the too many open files error during the loading phase after having several tables created to the database. I managed to avoid the current error with increasing the file handle limit: vi /etc/security/limits.conf #add for file handle #see lsof -p pid monetdb soft nofile 65536 monetdb hard nofile 65536 Now the system is running, but after 500 tables in MonetDb, I see about 17000 file handle listed with lsof -p command. The most of those are pointing to files in dbfarm folder. Is the files of all columns of all tables kept all the time? Is there formula to estimate the number file handles needed? Is there any limit how many tables or columns we can have in one MonetDb instance? The version used is "MonetDB Database Server v1.6 (Jul2012-SP1)" compiled from sources for RedHat 6. -- Jukka jukkakar@iki.fi