Duplicate message detection on failover - activemq

Question

We have ActiveMq 5.15.2 in following configuration:
PostgreSQL for persistance
two nodes, one in standby
JDBC master slave with shared database
static cluster discovery
Everything seams to be fine, failover works as expected, but sometimes during failover (or restart of whole cluster) we are observing following exception:
WARN [ActiveMQ NIO Worker 6] org.apache.activemq.transaction.LocalTransaction - Store COMMIT FAILED:java.io.IOException: Batch entry 2 INSERT INTO ACTIVEMQ_MSGS(ID, MSGID_PROD, MSGID_SEQ, CONTAINER, EXPIRATION, PRIORITY, MSG, XID) VALUES (...) was aborted: Unique-Constraint activemq_msgs_pkey Detail: key(id)=(7095330) alerady exists
ActiveMQ propagates this exception directly to the client.
I thought, that ActiveMQ would be able to recognise duplicated message, but something goes wrong here.....
The client tries to deliver message with already existing ID, should not ActiveMQ compare this message to one already existing in storage (if possible, depending on DB) and if both messages are the same just ignore second message?
Or maybe ActiveMQ assumes that duplicated messages are allowed to be persisted and our DB structure is not correct (constraint on id)?
CREATE TABLE activemq_msgs
(
id bigint NOT NULL,
container varchar(250),
msgid_prod varchar(250),
msgid_seq bigint,
expiration bigint,
msg bytea,
priority bigint,
xid varchar(250)
);
ALTER TABLE activemq_msgs
ADD CONSTRAINT activemq_msgs_pkey
PRIMARY KEY (id);
Should we drop activemq_msgs_pkey ?

Answer 1

Our JDBC configuration was incorrect - autocommit was set to false, and in result messages were propagated in DB with delay.