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 >> > >> >> >> >> >
