Hi Mike, Thanks a lot for the explanation! It makes perfect sense to me.
I just thought that you were able to do something with indexes in a such way that there is no need to preload everything from disk into memory when a query is executed over cold data. Then what does "execution over cold data" mean? I'm referring to the following sentence from the main page: *Object Query Language allows distributed query execution on hot and cold data, with SQL-like capabilities, including joins.* -- Denis On Fri, Aug 19, 2016 at 12:27 PM, Michael Stolz <mst...@pivotal.io> wrote: > Here's the thing... > > On any In-memory data grid, if you run a query before the data has been > loaded into memory, it is going to cause the exact same amount of disk i/o > to do the query as it will take to load everything into memory. > > And the system will still have to go ahead and load everything into memory > anyway so you're going to end up doing all that disk i/o TWICE. > > Geode DOES have a nice feature for key based access though. We actually > store the keys in a separate file from the data and we can load that file > very quickly. Then if you go after the data for one of those keys we can > lazily load it from disk on demand if it hasn't yet been loaded into memory. > > The Lucene integration work that is going on in Geode might also make it > possible to load the indexes first and lazily load the data based on > queries against the indexes. > > > -- > Mike Stolz > Principal Engineer, GemFire Product Manager > Mobile: 631-835-4771 > > On Fri, Aug 19, 2016 at 2:59 PM, Denis Magda <magda7...@gmail.com> wrote: > >> Hello Geode community, >> >> I've been investigating possibilities of Geode Persistence for a while >> and still can't get it clear whether I need to have all my data in memory >> if I want to execute OQL queries or OQL engine works over the persistence >> as well. >> >> My use case is the following. During the cluster startup I don't want to >> wait while all the data has been pre-loaded from the persistence to RAM and >> want to execute OQL queries right away. Is it feasible to implement with >> Geode? Please provide me with the links where I can read more about this. >> >> Regards, >> Denis >> > > -- Удачи, Денис Магда
