Apologies for the delay. Stefan Manegold wrote:
Which version of MonetDB are you using?
Database: MonetDB v5.20.5 Stefan Manegold wrote:
Which OS are you running on?
$ cat /etc/redhat-release CentOS release 5.5 (Final) Stefan Manegold wrote:
What kind of manchine/hardware are you running on, in particular how much memory does it have?
Intel(R) Core(TM)2 Quad CPU Q8400 @ 2.66GHz $ free -m total used free shared buffers cached Mem: 2983 2839 143 0 207 2425 -/+ buffers/cache: 206 2776 Swap: 4991 56 4935 (output of this command NOT taken while monetdb was adding primary keys) Stefan Manegold wrote:
Can you check what the machine is doing? Is it running out of physical memory and swapping, i.e., is the virtual size of the mserver5 (much) larger than the machine's physical memory size?
Memory usage from top reported 130% usage for memory. I'm assuming that means it was using most physical memory and swapping. Stefan Manegold wrote:
3. Is there anything I should do in future to speed up adding of primary keys?
In priciple not. We are aware that with data sizes (i.e., total size of all columns that the primary keys consists of) that significantly exceed main memory, adding the key (i.e., checking whether the data fulfills the key condition) does not work as efficiently as it could/should, in particular with multi-column keys --- we're working on that ... You could, though, run the ALTER TABLE statement in trace mode, i.e., `TRACE ALTER TABLE ...`, collect the output and send it to us for analysis; that could help us to improve the creation of large multi-column primary keys.
I'll issue this command over the weekend when I don't have anything planned for this machine. Thanks! -- View this message in context: http://old.nabble.com/Add-primary-key-performance-tp30397515p30474207.html Sent from the monetdb-users mailing list archive at Nabble.com.