Implementing UCP connections with Tomcat and Oracle
Installation Steps
- Make sure Tomcat server is stopped at this point. If running using shutdown.sh or shutdown.bat script.
- Download the latest Oracle JDBC driver from https://www.oracle.com/database/technologies/appdev/jdbc-ucp-19c-downloads.html. For example, ojdbc8-full.tar.gz.
- Remove ojdbc jar files like ojdbc*.jar or ojdbc*dms.jar from <FlexDeploy Home>/apache-tomcat-flexdeploy/lib.
- Copy ojdbc8.jar, ons.jar and ucp.jar from download archive to <FlexDeploy Home>/apache-tomcat-flexdeploy/lib.
- Update <FlexDeploy Home>/apache-tomcat-flexdeploy/conf/context.xml as shown below. Make sure to take backup of existing context.xml file.
Oracle
<Resource name="jdbc/flexdbDS" auth="Container" type="oracle.ucp.jdbc.PoolDataSource" factory="oracle.ucp.jdbc.PoolDataSourceImpl" connectionFactoryClassName="oracle.jdbc.pool.OracleDataSource" minPoolSize="0" maxPoolSize="100" initialPoolSize="0" autoCommit="false" url="jdbc:oracle:thin:@(DESCRIPTION=(ADDRESS_LIST=(ADDRESS=(PROTOCOL=tcp)(HOST=**HOSTNAME**)(PORT=**PORT**)))(CONNECT_DATA=(SERVICE_NAME=**SERVICE_NAME**)))" user="fd_admin" password="**FD_ADMIN_PASSWORD**" fastConnectionFailoverEnabled="true" validationQuery="select 1 from dual" testOnBorrow="true" useLocalSessionState="true" defaultAutoCommit="false"/>
- Replace **HOSTNAME** with database host name.
- Replace **PORT** with database listener port.
- Replace **SERVICE_NAME** with database service name.
- Replace **FD_ADMIN_PASSWORD** with password of fd_admin.
Key Points
- URL must be in the format listed in the example, the JDBC short format of host:sid:port should not be used.
- If RAC is used for the database, multiple nodes can be listed in the address list of the URL or it can point to the scan listener for the cluster.
- Sample URL for a RAC implementation that has a primary and secondary scan listener connecting to to a service name GOLD-CLOUD. This includes connection timeout, retry, and retry delay settings.
Sample RAC URL
url="jdbc:oracle:thin:@(DESCRIPTION = CONNECT_TIMEOUT=120) (RETRY_COUNT=20) (RETRY_DELAY=3) (TRANSPORT_CONNECT_TIMEOUT=3) (ADDRESS_LIST =(LOAD_BALANCE=on) (ADDRESS = (PROTOCOL = TCP) (HOST=primary-scan) (PORT=1521))) (ADDRESS_LIST =(LOAD_BALANCE=on) (ADDRESS = (PROTOCOL = TCP) (HOST=secondary-scan) (PORT=1521))) (CONNECT_DATA=(SERVICE_NAME = gold-cloud)))"
- Type and factory must reference the UCP driver.
- Actual timeout values will be environment specific. I would start with the defaults(not setting them) and then increase as needed.
- Set CONNECT_TIMEOUT to a high value to prevent logon storms.
- DO NOT use RETRY_COUNT without RETRY_DELAY
- Set LOAD_BALANCE= ON per ADDRESS_LIST to balance SCANsÂ
- Use one DESCRIPTION and more than one causes long delaysÂ
References
- https://www.oracle.com/technetwork/database/application-development/planned-unplanned-rlb-ucp-tomcat-2265175.pdf
- https://www.oracle.com/technetwork/database/enterprise-edition/ucp-transition-guide-129515.pdf
- https://docs.oracle.com/cd/E11882_01/java.112/e12265/connect.htm#CHDEEIJE
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