Kafka JDBC Sink Connector, insert values in batches - jdbc

Question

I receive a lot of the messages (by http-protocol) per second (50000 - 100000) and want to save them to PostgreSql. I decided to use Kafka JDBC Sink for this purpose.
The messages are saved to database by one record, not in batches. I want to insert records in PostgreSQL in batches with size 500-1000 records.
I found some answers on this problem in issue: How to use batch.size?
I tried to use related options in configuration, but it seems that they no have any effect.
My Kafka JDBC Sink PostgreSql configuration (etc/kafka-connect-jdbc/postgres.properties):
name=test-sink
connector.class=io.confluent.connect.jdbc.JdbcSinkConnector
tasks.max=3
# The topics to consume from - required for sink connectors like this one
topics=jsonb_pkgs
connection.url=jdbc:postgresql://localhost:5432/test?currentSchema=test
auto.create=false
auto.evolve=false
insert.mode=insert
connection.user=postgres
table.name.format=${topic}
connection.password=pwd
batch.size=500
# based on 500*3000byte message size
fetch.min.bytes=1500000
fetch.wait.max.ms=1500
max.poll.records=4000
I also added options to connect-distributed.properties:
consumer.fetch.min.bytes=1500000
consumer.fetch.wait.max.ms=1500
Although each a partition gets more than 1000 records per second, records are saved to PostgreSQL by one.
Edit: consumer options were added in other file with correct names
I also added options to etc/schema-registry/connect-avro-standalone.properties:
# based on 500*3000 byte message size
consumer.fetch.min.bytes=1500000
consumer.fetch.wait.max.ms=1500
consumer.max.poll.records=4000

Answer 1

I realised that I misunderstood the documentation. The records are inserted in database one by one. The count of the records inserted in one transaction depends on batch.size and consumer.max.poll.records. I expected that the batch insert was implemented the other way. I would like to have an option to insert records like this:
INSERT INTO table1 (First, Last)
VALUES
('Fred', 'Smith'),
('John', 'Smith'),
('Michael', 'Smith'),
('Robert', 'Smith');
But that seems impossible.