postgresql - Why does Liquibase want to dropPrimaryKey and addPrimaryKey? -

i have postgres databases generated eclipse link. between these databases not change, when run liquibase generating diffchangelog, generates changesets dropprimarykey , addprimarykey. don't understand why generates these records primary keys of tables. names, order of columns same both tables.

example of changeset

<changeset author="michal2 (generated)" id="1436872322297-8">         <dropprimarykey tablename="country_translation"/>         <addprimarykey columnnames="country_id, translations_id" constraintname="country_translation_pkey" tablename="country_translation"/>     </changeset> 

sql of original table

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 ) (   oids=false ); alter table country_translation   owner hotels; 

sql of reference table

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 ) (   oids=false ); alter table country_translation   owner hotels; 

liquibase command arguments

./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

this has been fixed liquibase 3.4.1 https://liquibase.jira.com/browse/core-2416