gistfile1.txt

# docker build -t tomaszalusky/xmin-example .
# docker run -d --name xmin-example tomaszalusky/xmin-example
# docker exec -it xmin-example /bin/bash -c ./test.sh

FROM postgres:9.6.11

WORKDIR /docker-entrypoint-initdb.d

RUN apt-get update && \
    apt-get install vim -y && \
    echo "sed -i 's/#track_commit_timestamp = off/track_commit_timestamp = on/g' /var/lib/postgresql/data/postgresql.conf" > updateconf.sh && \
    chmod a+r updateconf.sh && \
    echo "create table my_test (id bigserial primary key, text text, ins_time timestamp with time zone not null default now());" > createdb.sql
  
WORKDIR /

RUN echo "psql -U postgres -c \"begin; select pg_sleep(4); insert into my_test (text) values ('tx1 started first, committed second'); select pg_sleep(6); commit;\" &" > /test.sh && \
    echo "psql -U postgres -c \"select pg_sleep(2); begin; select pg_sleep(4); insert into my_test (text) values ('tx2 committed first'); select pg_sleep(2); commit;\" &" >> /test.sh && \
    echo "sleep 13" >> /test.sh && \
    echo "psql -U postgres -c \"select *,pg_xact_commit_timestamp(xmin) from my_test\"" >> /test.sh && \
    chmod +x /test.sh

ENTRYPOINT ["/docker-entrypoint.sh"]
CMD ["postgres"]