Created ticket: https://issues.apache.org/jira/browse/IGNITE-150
I named flag 'iterateOnStart'. Please suggest if you have any other ideas. On Wed, Jan 28, 2015 at 12:48 AM, Dmitriy Setrakyan <[email protected]> wrote: > +1 > > I do like disabling it by default as I think we should always err on the > side of performance. > > D. > > On Wed, Jan 28, 2015 at 7:56 AM, Vladimir Ozerov <[email protected]> > wrote: > > > +1 for adding such flag. > > > > Not sure about disabling it by default. Current behavior may be redundant > > for many cases, but it looks consistent and sensible for users who use it > > for the first time. > > > > On Wed, Jan 28, 2015 at 10:21 AM, Alexey Kuznetsov < > > [email protected]> > > wrote: > > > > > Could we print some warnings / performance suggestions in case of long > > > iterations over existing results? > > > > > > On Wed, Jan 28, 2015 at 2:11 PM, Valentin Kulichenko < > > > [email protected]> wrote: > > > > > > > Currently, when continuous query is executed, it first iterates over > > > > existing results before processing continuous updates. This iteration > > can > > > > take a lot of time and not always needed. > > > > > > > > Imagine simple scenario: > > > > > > > > - Load initial data from DB to cache; > > > > - Register continuous query for further updates that will happen > > while > > > > application is running; > > > > - Run the application. > > > > > > > > In most cases notifications on initial data are not needed, but you > get > > > > them regardless of whether you registered query before or after data > > > > loading. > > > > > > > > I think we should add a flag on continuous query that allows to > enable > > or > > > > disable this behavior. Also I think that it should be disabled by > > default > > > > because I really can't imaging a use case when you need to iterate > > > through > > > > the whole cache. Also it's not obvious what is happening in this > case - > > > if > > > > user was not attentive enough reading the documentation and there is > a > > > lot > > > > of data, he may think that query simply hanged during registration > > > process. > > > > > > > > Thoughts? > > > > > > > > > > > > > > > > -- > > > Alexey Kuznetsov > > > GridGain Systems > > > www.gridgain.com > > > > > >
