anchor.diff:  
   The request configures these options:
   
  -1. unwrapping Debezium's complex format into a simple one
  +1. extracting only the new rows state from Debezium's change data message
   2. extracting `id` field from the key `struct`, then the same key is used for the source and both destinations.
  -This is to overcome limitation of Elasticsearch connector that supports only `int`s and `string`s as keys.
  +This is to overcome limitation of Elasticsearch connector that supports only `int`s (of all sizes) and `string`s as keys. If we do not extract the `id` the messages will be filtered out by the connector because of unknown key type.
   3. use key from the event instead of generating a synthetic one
   4. type under which the events will be registered in Elasticsearch
   
  
positive.code: docker-compose up
  ----
  
  When all components are started we are going to register the Elasticsearch Sink connector writing into the ElasticSearch instance.
  We want to use the same key (primary id) in the source and both PostgreSQL and Elasticsearch.
  [source,bash,indent=0]
  ----
  
negative.code: 
  == Summary
  
  We set up a complex streaming data pipeline to synchronize MySQL database with another database and also with Elasticsearch instance.
  We managed to keep the same identifier across all systems which allows us to correlate records across the system as the whole.
  
  == About Debezium
  
  