On 2017-11-16 15:38, ajs6f wrote: >>> How much data? SSD vs >>> disk? How much free RAM for file cache? What else is on the machine? >>> Cold start or warm database? >> >> Machine data - Intel Xeon E312xx (Sandy Bridge) and 32 GB RAM > > How much heap have you allocated to Jena's JVM? What else (as Andy asked) is > going on on the machine? There is an important difference between heap and > free (free is available to the OS for file caching, heap is not).
I have two different setups on similar machines: - WildFly shared with other apps: JAVA_OPTS="-Xms64m -Xmx8192m -XX:MetaspaceSize=96M -XX:MaxMetaspaceSize=1024m -Djava.net.preferIPv4Stack=true" - WildFly just for the semantic app JAVA_OPTS="-Xms64m -Xmx512m -XX:MetaspaceSize=96M -XX:MaxMetaspaceSize=256m -Djava.net.preferIPv4Stack=true" On both the delay is quite similar. Maybe my problem is a setup configuration. > ajs6f > >> On Nov 16, 2017, at 9:34 AM, George News <[email protected]> wrote: >> >> On 2017-11-16 14:51, Andy Seaborne wrote: >>> >>> >>> On 16/11/17 13:42, Rob Vesse wrote: >>>> TDB does not store a separate list of graphs as it is a quad store >>>> i.e. it stores raw quads. >>>> >>>> Therefore, in order to list the available graphs it has to iterate >>>> over all the quads and track the unique values for the graph field. >>>> >>>> So what you are doing yourself is probably the best approach >>> >>> I have recently been doing some related queries (COUNT) and don't see >>> this issue but who knows? Details are missing. >> >> When I make a query to a specific graph it works really well and >> quickly. But the problem is that listing is taking too much. >> >>> How much data? SSD vs >>> disk? How much free RAM for file cache? What else is on the machine? >>> Cold start or warm database? >> >> Machine data - Intel Xeon E312xx (Sandy Bridge) and 32 GB RAM >> >>> An example database to try out would help. >> >> Database is over 20Gb now and has 200 named graphs, so unable to post it ;) >> >>>> >>>> Rob >>>> >>>> On 16/11/2017, 12:03, "George News" <[email protected]> wrote: >>>> >>>> Sorry for insisting on this matter, >>> >>> That's not how this works. >> >> I know that you answer whenever you have time, and I will never be able >> to thank you, but let's say in order to be "polite" it's better to >> apologize for insisting as this is like upping a post, which I really >> don't like. >> >>> Andy >>> >>>> but I really need to remove the >>>> delay and would love to understand how the system works, as >>>> otherwise I >>>> have to rework a big part of my code :( >>>> On 2017-11-15 12:02, George News wrote: >>>> > Hi, >>>> > >>>> > I would like to know if there is any way of speeding up >>>> > Dataset.listNames(). Currently running it on a TDB with 200 >>>> graphs it >>>> > takes something like 10 seconds. >>>> > >>>> > I think it is quite a lot, as there should be some index >>>> pointing to them. >>>> > >>>> > Could you please tell me how I can speed up? I'm now currently >>>> thinking >>>> > on uploading all the graphs names in memory when starting my >>>> service and >>>> > then use the names from memory. >>>> > >>>> > Regards, >>>> > Jorge >>>> > >>>> >>>> >>>> >>>> >>> > >
