On Mon, Oct 26, 2015 at 5:31 AM, Raul Kripalani <ra...@apache.org> wrote:
> Hi, > > Thanks all for chiming in. It seems like this feature could be of interest > to the user community, so I've opened a ticket to continue maturing the > idea there: > > https://issues.apache.org/jira/browse/IGNITE-1789 > > We may need to create a Wiki page later to collaborate around specifics and > design. > Thanks Raul. I agree that Wiki page may be in order. I have responded in the ticket. Take a look and see if you agree with my thinking. > Regards, > > *Raúl Kripalani* > PMC & Committer @ Apache Ignite, Apache Camel | Integration, Big Data and > Messaging Engineer > http://about.me/raulkripalani | http://www.linkedin.com/in/raulkripalani > http://blog.raulkr.net | twitter: @raulvk > > On Wed, Oct 21, 2015 at 10:06 AM, Raul Kripalani <ra...@apache.org> wrote: > > > Hey guys, > > > > LevelDb has a functionality called Snapshots which provides a consistent > > read-only view of the DB at a given point in time, against which queries > > can be executed. > > > > To my knowledge, this functionality doesn't exist in the world of open > > source In-Memory Computing. Ignite could be an innovator here. > > > > Ignite Snapshots would allow queries, distributed closures, map-reduce > > jobs, etc. It could be useful for Spark RDDs to avoid data shift while > the > > computation is taking place (not sure if there's already some form of > > snapshotting, though). Same for IGFS. > > > > Example usage: > > > > IgniteCacheSnapshot snapshot = > > ignite.cache("mycache").snapshots().create(); > > > > // all three queries are executed against a view of the cache at the > > point in time where it was snapshotted > > snapshot.query("select ..."); > > snapshot.query("select ..."); > > snapshot.query("select ..."); > > > > In fact, it would be awesome to be able to logically save this snapshot > > with a name so that later jobs, queries, etc. can run on top of it, e.g.: > > > > IgniteCacheSnapshot snapshot = > > ignite.cache("mycache").snapshots().create("abc"); > > > > // ... > > // in another module of a distributed system, or in another thread in > > parallel, use the saved snapshot > > IgniteCacheSnapshot snapshot = > > ignite.cache("mycache").snapshots().get("abc"); > > .... > > > > Named snapshotting can be dangerous due to data retention, e.g. imagine > > keeping a snapshot for 2 weeks! So we should force the user to specify a > > TTL: > > > > IgniteCacheSnapshot snapshot = > > ignite.cache("mycache").snapshots().create("abc", 2, TimeUnit.HOURS); > > > > Such functionality would allow for "reporting checkpoints" and "time > > travel", for example, where you want users to be able to query the data > as > > it stood 1 hour ago, 2 hours ago, etc. > > > > What do you think? > > > > P.S.: We do have some form of snapshotting in the Compute checkpointing > > functionality – but my proposal is to generalise the notion. > > > > Regards, > > > > *Raúl Kripalani* > > PMC & Committer @ Apache Ignite, Apache Camel | Integration, Big Data and > > Messaging Engineer > > http://about.me/raulkripalani | http://www.linkedin.com/in/raulkripalani > > http://blog.raulkr.net | twitter: @raulvk > > >
