Dear Javier, Thank you for your report. It is hard to assess the consequences/impact of your particular setup. Your report suggests that something else was also running on your platform during this sequence, at that particular time. It could mean the MonetDB was fighting with another process over resources, i.e. memory and disk bandwidth. It could also indicate a thrashing kernel on shared kernel resources. If the system persists during repetitive runs under controlled system settings and it is immune to query order, then we might look further into the issue. regards, Martin On 1/17/13 3:44 PM, Javier Picorel wrote:
Dear all,
I'm running MonetDB (Dec2011-SP2) on Sparc Solaris 10 u9. I'm testing the TPC-H queries using SF10 and SF100 as the scale factors. My machine has 4 cores and 32GB of RAM and my farm is on a disk array.
Unfortunately, there are some queries (e.g., Qry 7, 8, 9) that enters into phase in which the User/System time is 4% to 21% for a couple of minutes. Interestingly, the same issue doesn't show up on a Linux machine with a similar setup and the queries' system time is pretty low (<5%).
Interestingly, vmstat output doesn't show any disk activity during the phase where the process is just in system, only there are high values on "re" and "mf" fields. There is no swapping going on ("po" and "pi" values are 0 in vmstat).
These are the parameters of the DB:
type default database shared default yes nthreads default 4 optpipe default_pipe master default no slave default <unknown> readonly default no nclients default 64
The way that I test the query is by running just one at a time. How can I mitigate this OS time?
Thanks in advance, Javier
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