Multiple postgres connections with debezium connector

Question

When I create a kafka connect connector with the debezium connector, it results in four database connections. Three of them remain idle, while one works as the actual replication slot. I can't find any information about the expected number of database connections.

Here is my config that I post to /connectors

{
  "name": "my.source.connector",
  "config": {
    "connector.class": "io.debezium.connector.postgresql.PostgresConnector",
    "tasks.max": 1,
    "plugin.name": "pgoutput",
    "heartbeat.interval.ms": "0",
    "slot.name": "slotty_slot",
    "database.hostname": "localhost",
    "database.port": "5432",
    "database.user": "debezium",
    "database.password": "************",
    "database.dbname": "my_database",
    "database.server.name": "server_name",
    "topic.creation.default.replication.factor": "1",
    "topic.creation.default.partitions": "20"
  }
}

Is four connections normal? Or should it be one?

Answer 1

This was fixed by DBZ-5074. You should notice this being improved in the upcoming 1.9.3.Final or the Debezium 2.0 release due out later this year.