Add two value from two record

The important thing about example 4 is not that the data comes from jdbc, it is that all the events for a single task id come one after another. In your case the task id is a constant, so that would not work.

it is so simple I can't put my finger on what is going wrong.

'--java-execution true' just gets ever more broken.

If you disable the java execution engine then you should get

{
  "@version" => "1",
      "tags" => [
    [0] "_aggregatetimeout",
    [1] "_aggregatefinalflush"
],
"@timestamp" => 2020-07-31T19:23:58.136Z,
   "mytotal" => 6.85,
"%{subpool}" => "1"
}

With java execution the pipeline does not shutdown and you do not get this message

[2020-07-31T15:23:58,291][INFO ][logstash.pipeline        ][main] Pipeline has terminated {:pipeline_id=>"main", :thread=>"#<Thread:0x79b128a7 run>"}

even though the lines input has sent all the lines.

Alternatively add a file input that tails a non-existent file

input { file { path => "/tmp/foo.txt" sincedb_path => "/dev/null" start_position => beginning } }

and you will start getting

 {
      "tags" => [
    [0] "_aggregatetimeout"
],
  "@version" => "1",
   "mytotal" => 6.85,
"%{subpool}" => "1",
"@timestamp" => 2020-07-31T19:05:58.928Z
}

Again, this only happens if the java execution engine is disabled.

in sort I have to wait for this to get fixed.

I have given up on this for now.
Thought with different logic and setting that up.
basically I am gone a run another jdbc with total output of two type and create third record in index.