Server runs out of memory (Java VM heap) and freezes. In logging found:
WARN: [Caesium-1-2] [confluence.impl.hibernate.ConfluenceHibernateTransactionManager] doRollback Performing rollback. Transactions: ->[PluginReadWriteTX]: PROPAGATION-REQUIRED,ISOLATION_DEFAULT (session #561381725)
ERROR: [Caesium-1-2] [impl.schedule.caesium.JobRunnerWrapper] runJob Scheduled job com.atlassian.confluence.plugins.confluence-edge-index:flushEdgeIndexQueueJob#flushEdgeIndexQueue failed to run com.atlassian.bonnie.LuceneException: org.springframework.transaction.UnexpectedRollbackException: Transaction rolled back because it has been marked as rollback-only