Getting data in a Geode Server with a Partitioned Region

Question

I have a Geode system with one locator, three cache servers and one client. Inside these servers, there is a partitioned region which my data is in. What I am trying to do is that run a function on each server to get the data on that specific server. I wrote the function below for beginning:

public void execute(FunctionContext fc) {
    Cache cache = CacheFactory.getAnyInstance();
    // testRegion is a partitioned region
    Region<Object, Object> region = cache.getRegion("/testRegion");
    Set<Object> keys = region.keySet();
    Set keysTillSecondLast = new HashSet();
    int setSize = keys.size();
    Iterator keysIterator = keys.iterator();
    for(int i = 0; i < (setSize -1); i++)
    {
        keysTillSecondLast.add(keysIterator.next());
    }
    for (Object k : keysTillSecondLast) {
        fc.getResultSender().sendResult((Serializable) region.get(k));
    }
    Object lastResult = keysIterator.next();
    fc.getResultSender().lastResult((Serializable) region.get(lastResult));
}

There are 30 entries in the partitoned region. When I call the function above like this:

public void runFunction() {
    MyFunction function = new MyFunction();
    FunctionService.registerFunction(function);

    Execution execution = FunctionService.onServers(cache);
    ResultCollector collector = execution.execute(new MyFunction());
    List result = (List) collector.getResult();
    System.out.println(result);
}

The result list's size is 60 (duplicate entries). When I use FunctionService.onServer() method instead, than the list size is 30 which is all the data I have pushed. So is there a way to get only the data on a specific server? Like when I run the function it should return something like:

Data on Server1: ....
Data on Server2: ....
Data on Server3: ....

Answer 1

You need to use PartitionRegionHelper in your function body to get the local data. Something like:

@Override
public void execute(FunctionContext context) {
  RegionFunctionContext rfc = (RegionFunctionContext) context;
  Region r = PartitionRegionHelper.getLocalDataForContext(rfc);
  ...
}