Hi, after a while using MonetDB some general use questions pops up. I've collected some which answers I think will be of great help for any MonetDB user. * * *#1:* In the monetdb manpage we can read: *“The kill command immediately sends a SIGKILL and should only be used as last resort for a database that doesn't respond any more. Killing a database may result in (partial) data loss.”* * * 1.1 If kill is the last resort, what are the other options? * * *#2:* System monitor (Oct 2013)http://www.monetdb.org/Documentation/Cookbooks/SQLrecipes/monitor 2.1 Will this be available in October or is there a new estimate? 2.2 Does the current development version include this feature yet so we can test it? I'm interested mainly in the methods sys.pause(qtag), sys.resume(qtag) and sys.stop(qtag), *specially sys.stop(qtag)*. 2.4 Is there some alternative method already available in the Feb2013 release to achieve this action? *#3:* In the monetdb manpage we can read about the *nclients* property: *“Sets the maximum amount of clients that can connect to this database at the same time. Setting this to a high value is discouraged.” * 3.1 What do you consider as a high value? Fabian Groffen stated in a similar question *"Concurrency is always a problem for MonetDB, since in the ideal case it means the processes are fighting for resources with each other." * 3.2 Does this mean (theoretically) that if I can run Query A in 10s in a system with resources R (Ram, Disk, Processor), with Rx2 I can run Query A and B (equivalent in effort to A) in the same 10s? *#4:* www.monetdb.org/Documentation/Manuals/SQLreference/Transactions: *"WARNING. The tuples being deleted are only marked as such. They do not reduce the table size. It calls for a vacuum cleaning algorithm."* * * I've found the /usr/lib/monetdb5/createdb/20_vacuum.sql script and after some googling I found the following post* * http://mail.monetdb.org/pipermail/users-list/2011-August/005051.html without an answer. 4.1 Does the following sequence frees the space of the deleted rows? sql>delete from sys.transfer_ip ; 651950 affected rows (117.620ms) sql>call vacuum('sys','transfer_ip'); Best regards, Ruben Silva