>> 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). 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 >>> > >>> >>> >>> >>> >>
