I am crossposting this to dev list as well. So, is there a way to introduce custom aggregate function? I assume no.
But even if we have such ability, writing and plugging such custom function seem to be much harder to do than direct reducer/transformer from java code. However, this is not very common usecase in SQL, I think. I think it would be very nice to support custom aggregate functions. As far as java-reducers - this is not very intuitive and I would skip adding them back if custom aggregate is possible. Sergi, Alex, can you please share your opinions? --Yakov 2015-06-09 22:21 GMT+03:00 Dmitriy Setrakyan <[email protected]>: > Also, if you need to return only a portion of the object (just a few > fields), you can use SqlFieldsQuery and select only specific fields: > > select a, b, c from Person... > > D. > > On Tue, Jun 9, 2015 at 1:20 PM, fluffy <[email protected]> wrote: > >> Using GridGain, I used to be able to associate a GridClosure method with a >> GridCacheQuery. You could simply pass this Closure method into the >> GridCacheQuery.execute() function and it would perform a function on each >> cache element that matched the SQL query. >> >> This basically consolidated a number of tasks: >> >> - Instead of receiving entire objects from a query, a much smaller result >> value was sent back to the node that initiated the query >> - Allowed for the specification of some functionality within each Cache >> Element rather than being a fairly dull data store >> - Allowed for distributed processing of Cache Element information on the >> node that each valid element existed before being aggregated/merged on the >> calling node >> >> I do not see this functionality as having been ported to the Ignite >> release. >> At least not directly. Is there a way to do this in the current Ignite >> version? >> >> I was looking at either a ScanQuery or using the AffinityRun methods, but >> the later don't seem to allow me to perform an SQL query first to limit >> the >> Cache Elements.... >> >> >> >> -- >> View this message in context: >> http://apache-ignite-users.70518.x6.nabble.com/Closure-method-on-a-Cache-Query-tp456.html >> Sent from the Apache Ignite Users mailing list archive at Nabble.com. >> > >
