seems like this is related to my problem.. I am having the same experience with a similar query with group by count.
thanks. Yuhan On Wed, Sep 19, 2012 at 10:48 AM, Bill Roberts <[email protected]> wrote: > Thanks Andy. Further info inline. > > >> > > > > Depending on load, but I doubt at 20e6 it's going to take 10+mins. It's > not a cheap query but it's not completely bad. If GC went mad with > close-to-full thrashing, then maybe but if so, then the query will probably > soon run out of heap. > > > > Has this server crashed and rebooted? > Not sure - I think we may have had to force a reboot at one point, without > stopping fuseki first, though as this instance doesn't get updated very > often, it's unlikely that this would have happened during a write. > > > Has data been incrementally added? > Yes > > > Any exceptions in the log when doing an update? > Not that I'm aware of. > > > > > It is possible that one of the old bugs has caused a loop in the index. > The query will never finish, but the amount of memory will not go up - > it's in a CPU loop. > > > > Try this: > > > > SELECT (count(*) AS ?count) WHERE { ?s ?p ?o } > > > > and see if it finishes. Not a perfect test but indicative. > I tried this. It didn't finish after 6 minutes, so I killed it (restarted > fuseki). > Memory use was high but not rising while the query was running. > CPU was maxed out (on one core). > Incidentally, fuseki in this state was quite hard to kill - it wasn't > responding to stopping via /etc/init.d - I had to kill -9 the java process. > > If the code is in a CPU loop, might that explain why the timeout doesn't > work - because the code never gets a chance to check whether it should give > up on this query? > > > > > >> (In any case I will upgrade that server to Fuseki 0.2.4 - this is a > >> good reminder that I should do that). > > > > Yes! > Have upgraded to 0.2.4 > Repeated the count-everything test, with same outcome. > > If a looped index is the problem, presumably the only solution is to > reload all the data into a new TDB instance? > > > > >> > >> Thanks > >> > >> Bill > >> > >> > >> > > > > -- Yuhan Zhang Senior Software Engineer OneScreen Inc. [email protected] <[email protected]> www.onescreen.com (949) 525-4825 Ext: 177 The information contained in this e-mail is for the exclusive use of the intended recipient(s) and may be confidential, proprietary, and/or legally privileged. Inadvertent disclosure of this message does not constitute a waiver of any privilege. If you receive this message in error, please do not directly or indirectly print, copy, retransmit, disseminate, or otherwise use the information. In addition, please delete this e-mail and all copies and notify the sender.
