Thanks! I am trying to understand when and how data is moved from off-heap to on heap, particularly when using SQL. I took a look at the wiki <https://cwiki.apache.org/confluence/display/IGNITE/Ignite+Durable+Memory+-+under+the+hood> but still have a few questions
My understanding is that data is always store off-heap 1) In what format is data stored off heap? 2) What happens when a SQL query is executed, in particular - How is H2 used? How is data loaded in H2? What if some of the data is on disk? - When is data loaded into heap, and how much? Is only the output of H2 loaded, or everything? - How is the reduce stage performed? Is it performed only on one node (hence that node needs to load all the data into memory) 3) What happens when Ingite runs out of memory during execution? Is data evictied to disk (if persistence is enabled)? 4) Based on the code, it looks like I need to set my data region size to at most 50% of available memory (to avoid the warning), this seems a bit wastefull. 5) Do you have any general advice on benchmarking the memory requirpement? So far I have not been able to find a way to check how much memory each table takes on and off heap, and how much memory each query takes. Cheers, Eugene On Fri, Aug 24, 2018 at 8:06 AM, NSAmelchev <nsamelc...@gmail.com> wrote: > Hi Eugene, > > Yes, it's a misprint as Dmitry wrote. > > Ignite print this warning if nodes on local machine require more than 80% > of > physical RAM. > > From code, you can see that total heap/offheap memory summing > from nodes having the same mac address. This way calculates total memory > used > by the local machine. > > -- > Best wishes, > Amelchev Nikita > > > > -- > Sent from: http://apache-ignite-users.70518.x6.nabble.com/ >
