I'm seeing some behavior that makes me wonder if mserver5 leaks.
I'm using Ubuntu 9.04 w/ 32-bit i386 and 500 MB of RAM. This is 2009Nov CVS.
Does this sequence of steps and memory usage look right?
1. Reboot the server and start merovingian 0m -- mserver5 RSS (not running) 417m -- free memory reported by top 78m -- used 5m -- buffers 2. Destroy then create database 15m -- mserver5 RSS 392m -- free memory reported by top 3. Add tables to database 21m -- mserver5 RSS 378m -- free memory reported by top 4. Import a small table (38,000 rows, autoincr int + varchar(1024)) 29m -- mserver5 RSS 350m -- free memory reported by top 5. Repeat steps 2 through 4 three times. 29m -- mserver5 RSS !!! 225m -- free memory reported by top 6. Shut down merovingian !!! 251m -- free memory reported by top 242m -- used 136m -- buffers
Why is top only showing 251m of free memory?
Yesterday, the system started to swap when free memory, as reported by top, was exhausted.
And I bet I could get it to swap if I ran lots more iterations in step 5 above.
I know that having free close to zero is a good thing, as it means you are using your RAM, but that swapping is never good on a database server. :)
I'm not using the server for anything else at the moment, other than SSH and transferring data from SQLite to MonetDB via mclient and files of SQL commands.
As a related question, what is the minimum RAM need to run MonetDB? I'd like to get it running on an old slow computer running OpenBSD to check how well Monet handles memory pressure and to turn on OpenBSD's paranoid malloc options. Are there some knobs I can turn to make monetdb5 run when there is only 100MB of free memory after the OS starts up?
That swapping yesterday got me a nervous about stability, especially since stopping and restarting merovingian didn't give the memory back.
Thanks,
m