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I am trying to run some TPC-H queries to get a sense for how large of databases MonetDB can handle. I am currently trying a factor 20 database. I notice that on query 9, it is taking over two hours (still running). In "top" it claims that virtual memory for the process started at 27 GB or so, and is now down to 10 GB. What is noteworthy is that CPU usage is pretty small, at 2%. I previously observed 80-100% with a factor 1 database.

Does this mean you got the sf-20 loaded? What fixed your problem with loading?

Yes, I got it loaded. Since I had broken up the file into smaller chunks, I just restarted on the last chunk that it failed on before the crash. Eventually, it went through all of the tables.

The low cpu usage indicates that MonetDB is waiting for IO. I'll later this week try to repeat your experiment on a similar system. Then I'll have more input on how to improve things.

After writing the email I noticed that system CPU wait time was at 25%, with MonetDB at 2% and idle at 73% or so. So, yes, it is waiting on IO. Perhaps it is just my hardware. I did disable the 2 GB swap partition and rerun. After doing so, execution time did improve somewhat. I am not sure if this means one should always disable swap on a MonetDB system, since the system drive is slower than the data drives. I will try another experiment and let you know the results. = Series 7 NASD Exam Training Series 7 and related NASD Exam Books, software and web based training. http://a8-asy.a8ww.net/a8-ads/adftrclick?redirectid=16e765a220119782741a407f... -- Powered by Outblaze