High memory utilization due to Oracle JDBC driver in JBoss EAP

Issue

• The class oracle.jdbc.driver.BlockSource$ThreadedCachingBlockSource fills the heap space memory
• We have a problem when enabling the Red Hat single sign-on 7.3.8 with the connection to the Oracle v.12.1.0.2.0 database, as it indicates the following errors:

[0m2020-11-12 09:58:43,280 INFO  [org.keycloak.connections.jpa.updater.liquibase.LiquibaseJpaUpdaterProvider] (ServerService Thread Pool -- 58) Initializing database schema. Using changelog META-INF/jpa-changelog-master.xml
[0m09:58:43,280 INFO  [org.keycloak.connections.jpa.updater.liquibase.LiquibaseJpaUpdaterProvider] (ServerService Thread Pool -- 58) Initializing database schema. Using changelog META-INF/jpa-changelog-master.xml
[0m2020-11-12 10:03:36,340 ERROR [org.jboss.as.controller.management-operation] (Controller Boot Thread) WFLYCTL0348: Timeout after [300] seconds waiting for service container stability. Operation will roll back. Step that first updated the service container was 'add' at address '[
    ("core-service" => "management"),
    ("management-interface" => "http-interface")
]'
[31m10:03:36,340 ERROR [org.jboss.as.controller.management-operation] (Controller Boot Thread) WFLYCTL0348: Timeout after [300] seconds waiting for service container stability. Operation will roll back. Step that first updated the service container was 'add' at address '[
    ("core-service" => "management"),
    ("management-interface" => "http-interface")
]'

[...]

[33m10:03:40,198 WARN  [com.arjuna.ats.arjuna] (Transaction Reaper Worker 0) ARJUNA012121: TransactionReaper::doCancellations worker Thread[Transaction Reaper Worker 0,5,main] successfully canceled TX 0:ffff0a3e0c09:-70b7065a:5fad317c:12

[...]

Caused by: liquibase.exception.MigrationFailedException: Migration failed for change set META-INF/jpa-changelog-1.9.0.xml::1.9.0::mposolda@redhat.com:
     Reason: liquibase.exception.UnexpectedLiquibaseException: java.sql.SQLException: IJ031070: Transaction cannot proceed: STATUS_ROLLEDBACK
    at liquibase.changelog.ChangeSet.execute(ChangeSet.java:607)
    at liquibase.changelog.visitor.UpdateVisitor.visit(UpdateVisitor.java:51)
    at liquibase.changelog.ChangeLogIterator.run(ChangeLogIterator.java:79)
    at liquibase.Liquibase.update(Liquibase.java:214)
    at liquibase.Liquibase.update(Liquibase.java:192)
    at liquibase.Liquibase.update(Liquibase.java:188)
    at org.keycloak.connections.jpa.updater.liquibase.LiquibaseJpaUpdaterProvider.updateChangeSet(LiquibaseJpaUpdaterProvider.java:182)
    at org.keycloak.connections.jpa.updater.liquibase.LiquibaseJpaUpdaterProvider.update(LiquibaseJpaUpdaterProvider.java:102)
    ... 59 more
Caused by: liquibase.exception.UnexpectedLiquibaseException: java.sql.SQLException: IJ031070: Transaction cannot proceed: STATUS_ROLLEDBACK
    at liquibase.database.jvm.JdbcConnection.getURL(JdbcConnection.java:79)
    at liquibase.executor.jvm.JdbcExecutor.execute(JdbcExecutor.java:66)
    at liquibase.executor.jvm.JdbcExecutor.execute(JdbcExecutor.java:113)
    at liquibase.database.AbstractJdbcDatabase.execute(AbstractJdbcDatabase.java:1277)
    at liquibase.database.AbstractJdbcDatabase.executeStatements(AbstractJdbcDatabase.java:1259)
    at liquibase.changelog.ChangeSet.execute(ChangeSet.java:582)
    ... 66 more
Caused by: java.sql.SQLException: IJ031070: Transaction cannot proceed: STATUS_ROLLEDBACK
    at org.jboss.jca.adapters.jdbc.WrapperDataSource.checkTransactionActive(WrapperDataSource.java:272)
    at org.jboss.jca.adapters.jdbc.WrappedConnection.checkTransactionActive(WrappedConnection.java:2002)
    at org.jboss.jca.adapters.jdbc.WrappedConnection.checkStatus(WrappedConnection.java:2017)
    at org.jboss.jca.adapters.jdbc.WrappedConnection.checkTransaction(WrappedConnection.java:1991)
    at org.jboss.jca.adapters.jdbc.WrappedConnection.getMetaData(WrappedConnection.java:977)
    at liquibase.database.jvm.JdbcConnection.getURL(JdbcConnection.java:77)
    ... 71 more