As a database we use PostgreSQL. Application uses spring libraries, and transaction is managed by spring. Transactional annotation is used correctly, where it is needed as read-only, and where it is used with write abilities. But in logs we occasinally see exception
2020-12-30 11:39:13.513 [jmsContainer-8] ERROR o.h.e.jdbc.spi.SqlExceptionHelper - ERROR: cannot execute nextval() in a read-only transaction
2020-12-30 11:39:13.515 [jmsContainer-8] ERROR o.s.t.s.TransactionSynchronizationUtils - TransactionSynchronization.afterCompletion threw exception
javax.persistence.PersistenceException: org.hibernate.exception.GenericJDBCException: could not extract ResultSet
at org.hibernate.internal.ExceptionConverterImpl.convert(ExceptionConverterImpl.java:147)
at org.hibernate.internal.ExceptionConverterImpl.convert(ExceptionConverterImpl.java:155)
at org.hibernate.internal.ExceptionConverterImpl.convert(ExceptionConverterImpl.java:162)
at org.hibernate.internal.SessionImpl.firePersist(SessionImpl.java:780)
at org.hibernate.internal.SessionImpl.persist(SessionImpl.java:758)
at jdk.internal.reflect.GeneratedMethodAccessor2794.invoke(Unknown Source)
at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.base/java.lang.reflect.Method.invoke(Method.java:566)
at org.springframework.orm.jpa.SharedEntityManagerCreator$SharedEntityManagerInvocationHandler.invoke(SharedEntityManagerCreator.java:301)
at com.sun.proxy.$Proxy226.persist(Unknown Source)
Connections to PostgreSQL is provided through pg_bouncer, and pool_mode=sesssion, the server_reset_query=DISCARD ALL.
We tried restarting the pg_bouncer, though maybe some connection by default set read-only and being kept alive, but it did not help. Any thoughts?