Why does Liquibase want to dropPrimaryKey and addPrimaryKey?

General Discussion
1

I have Postgres databases generated with Eclipse Link. Between these databases is not any change, but when I run liquibase for generating diffChangeLog, it generates changesets with dropPrimaryKey and addPrimaryKey. I don’t understand why it generates these records for all primary keys of all tables. Names, order of columns are the same for both tables.

Example of changeset

Sql of original table
  1. CREATE TABLE country_translation ( country_id bigint NOT NULL, translations_id bigint NOT NULL, CONSTRAINT country_translation_pkey PRIMARY KEY (country_id, translations_id), CONSTRAINT fk_country_translation_country_id FOREIGN KEY (country_id) REFERENCES country (id) MATCH SIMPLE ON UPDATE NO ACTION ON DELETE NO ACTION, CONSTRAINT fk_country_translation_translations_id FOREIGN KEY (translations_id) REFERENCES translation (id) MATCH SIMPLE ON UPDATE NO ACTION ON DELETE NO ACTION ) WITH ( OIDS=FALSE ); ALTER TABLE country_translation OWNER TO hotels;
Sql of reference table
  1. CREATE TABLE country_translation ( country_id bigint NOT NULL, translations_id bigint NOT NULL, CONSTRAINT country_translation_pkey PRIMARY KEY (country_id, translations_id), CONSTRAINT fk_country_translation_country_id FOREIGN KEY (country_id) REFERENCES country (id) MATCH SIMPLE ON UPDATE NO ACTION ON DELETE NO ACTION, CONSTRAINT fk_country_translation_translations_id FOREIGN KEY (translations_id) REFERENCES translation (id) MATCH SIMPLE ON UPDATE NO ACTION ON DELETE NO ACTION ) WITH ( OIDS=FALSE ); ALTER TABLE country_translation OWNER TO hotels;
Liquibase command with arguments
  1. ./liquibase \ --driver=org.postgresql.Driver \ --classpath=/home/michal2/tools/postgresql-jdbc-driver/postgresql-jdbc.jar \ --changeLogFile=changelog-hotels.xml \ --url="jdbc:postgresql://localhost/hotels" \ --username=hotels \ --password=hotels \ --defaultSchemaName=public \ --logLevel=info \ diffChangeLog \ --referenceUrl="jdbc:postgresql://localhost/hotels_liquibase" \ --referenceUsername=hotels \ --referencePassword=hotels \ --referenceDefaultSchemaName=public
I'm using version 3.4.0