Pre-calculated JOIN queries as map in ignite
<p>I am new to ignite and POCing currently. 
I have a question regarding ways to store/load data in map. It's bit tricky and strange requirement. 
Example:</p>

<blockquote>
  <p>I have Employee, Department, Project [Tables in database] + [Entity classes in application]. 
  But I don't want to store each of these in a separate map in memory but rather I want to store pre-calculated join results in a designated map.</p>
</blockquote>

<p>Dynamic Query : select employeeId,employeeName,departmentName,projectName,projectStart,projectEnd from Employee,Department,Project where $JOIN</p>

<p>I know at least before hand that, what would be key fields and what would be value fields. From above example, I can denote my "Map" as shown below, </p>

<p>Key : Set (employeeId,departmentId)
Value : List (employeeName,value),(departmentName,value),(projectName,value),(projectStart,value),(projectEnd,value)</p>

<p>So you can see with every pair of (employeeId,departmentId) I would be having multiple values associates with it. But dilemma is I don't have domain model/entity pojos before hand. Such dynamic views/maps can be added flexibly so that we don't have to go and change domain/entity model every time. <strong>We don't want to do joins/calculations every time for thousands of such client request on every call.</strong> </p>

<p>Is it possible to fire such join queries using MapLoader or by any other means?
I can think of Map with (Key=Set, Value = List)as data structure to store final results.Any other better alternative?</p>

<p>Could there be any performance issues while retrieving values from such map based on keys?
Any memory optimizations I should take care of?</p>

<p>Thanks,
Dharam</p>