tqtrung@comp.nus.edu.sg wrote:

Dear all, I am a PhD student at School of Computing, NUS, Singapore. Currently, I used MonetDB as the DBMS to do some experiments. I issue a query with about 10 joins, but the system responds with the following errors:

Please inform us about the platform and distribution you are useing.

!MALException:algebra.join:GDKerror !ERROR: GDKload: cannot mmap(): name=45/4542, ext=head.priv !OS: Cannot allocate memory

this typically is an error when the join algorithm can not allocated enough memory to hold the intermediate result. For example, on a 32-bit system this might cause a problem quickly. If the join result should fit in memory, then there might be a problem in the estimation of the intermediate size needed. For this we need more information, such as the cardinality of the operands and properties obtained by bat.info()

!ERROR: GDKload failed: name=45/4542, ext=head.priv !ERROR: GDKload: cannot mmap(): name=45/4542, ext=tail.priv !OS: Cannot allocate memory !ERROR: GDKload failed: name=45/4542, ext=tail.priv !ERROR: GDKload: cannot mmap(): name=45/4542, ext=head.priv !OS: Cannot allocate memory !ERROR: GDKload failed: name=45/4542, ext=head.priv !ERROR: GDKload: cannot mmap(): name=45/4542, ext=head.priv !OS: Cannot allocate memory !ERROR: GDKload failed: name=45/4542, ext=head.priv !ERROR: GDKload: cannot mmap(): name=44/4401, ext=tail.priv !OS: Cannot allocate memory !ERROR: GDKload failed: name=44/4401, ext=tail.priv

I also try to change the parameter in monetdb5.conf about the memory: gdk_maxsize and gdk_vm_minsize but it still does NOT work.

please don't play with these settings. They only control a thread for flushing dirty pages to disk.

Could you please help me to figure out which parameters I could change to make it work.

Thank you very much Trung