Hi Henry, sorry for the inconvenience. We are not aware of any changes that might trigger the phenomenon you describe. In fact, we did do quite some performance testing before releasing Dec2011, and found and fixed some performance problems that had sneaked in. Having said that, do I understand correctly, that your SQL queries run fine (fast) both directly from your BI tool and via DBVisualizer when using MonetDB Oct2010-SP1, and also when run via DBVisualizer in MonetDB Dec2011, but run single-threaded and much slower when your BI tool sends the queries directly to MonetDB Dec2011? How does your BI tool connect to MonetDB? ODBC, JDBC, plain MAPI, ? To further analyze this issue, it would be great, if you could provide us with the following information: - your database schema (e.g., as SQL DDL statements) - a representative sample query (in SQL) - the output of running (on your database) your query prefixed with PLAN, EXPLAIN & TRACE (one at a time), if possible both on MonetDB Oct2010-SP1 & MonetDB Dec2011. Thanks! Stefan On Sun, Feb 12, 2012 at 10:39:36PM -0800, Henry Addington wrote:
Hi:
We are testing Dec 2011 Release to upgrade from Oct 2010 SP1 release on CentOS 5.2 64-bit with 100+ GB memory. We have a BI tool that users use to generate various reports. We have access to the SQL statements that get generated by the BI tool and sent to the MonetDB. So, we know exactly the SQL statements that are being sent to MonetDB.
One very odd thing that we are seeing the December release is that the reports from the BI tool are very, very slow (x10 - x15 from Oct releasee). It is obvious why looking at the server resource use. It looks like only 1 cpu is being used for all the queries! However, if I take the SQL statements generated by the BI tool and run them in DBVisualizer, all 20 cpu cores are used and the results return quickly. I am at a loss as to why we are seeing such different performance from identical SQL statements...
Is there a configuration setting or something in the December release that we overlooked? Can you please help us troubleshoot? Thank you.
HS
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