Update existing data in druid (metric)

Hi -

I am currently having issues ingesting multiple files in druid (especially having issues with the metric column). I have 3 different files that I want to load in druid periodically (say once a day).So first I did a data ingestion using ‘static’ input spec with a metric column (say ‘Count1’). Then I do a data ingestion again for data in second file using type ‘multi’ with dataSource = “”. My config that I am using for ingesting second file looks like this -

“ioConfig” : {

"type" : "hadoop",

 "inputSpec" : {

    "type" : "multi",

    "children" : [

        {

           "type" : "dataSource",

           "ingestionSpec" : {

                "dataSource" : "DS1",

                "intervals" : ["2018-04-05/2018-04-07"]

           }

        },

        {

            "type" : "static",

            "paths" : "<Path to File number 2>"

        }

    ]

 }

},

“dataSchema” : {

“dataSource” : “DS1”,

“granularitySpec” : {

   "type" : "uniform",

   "segmentGranularity" : "hour",

   "queryGranularity" : "hour",  

   "intervals" : [""2018-04-05/2018-04-07"]

},

“parser” : {

 .........

},

“metricsSpec” : [

  {"name" : "Count2"}

]

},

Question is - When I ingest data for first file - I see all the data and metric column (Count1 with values), but when I ingest data for file 2 using above config I see the new metric column (Count2 with values) but somehow the first metric column (Count1) now has all 0 in it.

What I want to see is the data from all the files get appended to the existing data and the metric columns to have values accordingly so at the end I can see all the metric columns and SUM values for Count1, Count2 and Count3.

Can someone please help to point out what I am doing wrong? I have referred http://druid.io/docs/latest/ingestion/update-existing-data.html

but I fully don’t understand the example mentioned there, especially what the dataSource test1 defined in the example or if I need to set the segments in my config and if so how?

I am fairly new to druid. Any help will be appreciated.