Hi all,
This I feel sure is "pilot error"; I am messing something up in my perl script to create the db. Have a tiny collection of 6 documents 75kb when loaded. It seems to load ok but when I go to use it I am getting Out of Main Memory errors. The JVM is 4gb using -Xms and -Xmx options on the java command to start the basex server (on an 8gb VM).
On reviewing the logs I can see that my client is not doing a CLOSE for the database -- yesterday's log showed 175 OPENs and only 31 closes -- OOPS!! Ok, so I start getting this:
OPEN chaingang Error: Out of Main Memory. 11286.05 ms I can see in top the JVMs ram just being gobbled up rapidly until it runs out and this message appears.
Yes, I know I need to fix my clients but is it possible that even when the clients session closes, somehow the database is being kept open, and eventually we run out of memory? But that doesn;t really fit with the "gobbling ram" I am seeing, unless the former situation triggers the latter.
IF this is the issue, could the basex server be made to nicely close any databases open in a session when that session is closed or the pipe gets broken?
# when trying to recover 2010-08-31.log:22:24:11.781 DROP DB chaingang Error: Database 'chaingang' is currently locked.
Or of a db has become corrupted somehow, could it cause such message? Are there any integrity check commands on the horizon?
I feel a bit nervous about these kinds of memory errors as I operate in a VSphere v4 (VMWARE) environment and my JVM monitoring skills are rudimentary -- the JVM does look like it has a nice big contiguous slab of ram to work with. Clearly something bad/silly I have done is triggering this behaviour: basex just "runs away" with ram.
Any thoughts? Has the api interface changed -- my perl client dates back to late March?
Sorry to be so vague.
Any similarly vague clues most welcome.
On a similar vien, my web interface/query controller is modperl2 under apache, which means the script sits resident in ram. I have it opening/closing a basex session on each request cycle (and am about to go check what I do when it closes!). Perhaps it would be far better to have the basex connection done in the apache initialisation stage (when apache2 launches the modperl2 modules) so the session just sits there until apache restarts. Then each request cycle should just open/close the database? I ask here as it could possibly be related to my grief above. If not my apologies for confusing the matter.
I am using this Sun jdk: /opt/java/jdk1.6.0_18/bin/java. Kind of regretting not using openSolaris as my OS platform rather than Linux. I do so love its trace facilities and its a great Java platform. I'm using 64bit Linux: 2.6.27-17-server #1 SMP Fri Mar 12 02:48:52 UTC 2010 x86_64 GNU/Linux ; and BaseX 6.2.6 [Server]
Best wishes all,
Sandra