Update deleted RDBMS entries in Elasticsearch using Logstash jdbc input plugin

[RRSR (Raj Rajeshwar Singh Rathore)]

I am trying to sync the RDBMS (postgres) data to Elasticsearch using Logstash and it works fine.
Logstash configuration file:

input {
  jdbc {
    jdbc_driver_library => "/home/raj/Downloads/postgresql-42.2.23.jar"
     jdbc_driver_class => "org.postgresql.Driver"
    jdbc_connection_string => "jdbc:postgresql://localhost:5432/local_test"
    jdbc_user => "postgres"
    jdbc_password => ""
    jdbc_paging_enabled => true
    tracking_column => "unix_ts_in_secs"
    use_column_value => true
    tracking_column_type => "numeric"
    schedule => "*/5 * * * * *"
    statement => "SELECT *, extract(epoch FROM modification_time) AS unix_ts_in_secs FROM es.es_table WHERE (extract(epoch FROM modification_time)) > :sql_last_value AND modification_time < NOW() ORDER BY modification_time ASC"
  }
}
filter {
  mutate {
    copy => { "id" => "[@metadata][_id]"}
    remove_field => ["id", "@version", "unix_ts_in_secs"]
  }
}
output {
  # stdout { codec =>  "rubydebug"}
  elasticsearch {
      index => "rdbms_sync_idx"
      document_id => "%{[@metadata][_id]}"
  }
}

Now if any record is deleted in postgres then to update the same in Elasticsearch trying to follow the first approach:

What about deleted documents?

The astute reader may have noticed that if a document is deleted from MySQL, then that deletion will not be propagated to Elasticsearch. The following approaches may be considered to address this issue:

1. MySQL records could include an "is_deleted" field, which indicates that they are no longer valid. This is known as a "soft delete". As with any other update to a record in MySQL, the "is_deleted" field will be propagated to Elasticsearch through Logstash. If this approach is implemented, then Elasticsearch and MySQL queries would need to be written so as to exclude records/documents where "is_deleted" is true. Eventually, background jobs can remove such documents from both MySQL and Elastic.
2. Another alternative is to ensure that any system that is responsible for deletion of records in MySQL must also subsequently execute a command to directly delete the corresponding documents from Elasticsearch.

Link: How to keep Elasticsearch synchronized with a relational database using Logstash and JDBC

Now how to check if the record was deleted in postgres or not and how to get the updated value for is_deleted and update the same in Elasticsearch?