Java application not using Transparent Application failover in Oracle database

Question

I have a customer that have a RAC environment (2 nodes, database version is 11gR2).

Clusterware version:

[grid@server2 ~]$ crsctl query crs releaseversion
Oracle High Availability Services release version on the local node is [11.2.0.4.0]
[grid@server2 ~]$ crsctl query crs activeversion
Oracle Clusterware active version on the cluster is [11.2.0.4.0]

Their aplication not use correctly the TAF (transparent application failover)

After some research I've tested using swingbanch and I've found the same behavior in my LAB environment:

INST_ID USERNAME   SERVER    SERVICE_NAME         PROGRAM              STATUS   FAILOVER_TYPE FAILOVER_M FAI
---------- ---------- --------- -------------------- -------------------- -------- ------------- ---------- ---
         1 SOE        DEDICATED mootdb_prod          JDBC Thin Client     ACTIVE   NONE          NONE       NO
         1 SOE        DEDICATED mootdb_prod          sqlplus.exe          INACTIVE SELECT        BASIC      NO
         1 SOE        DEDICATED mootdb_prod          JDBC Thin Client     ACTIVE   NONE          NONE       NO
         1 SOE        DEDICATED mootdb_prod          JDBC Thin Client     ACTIVE   NONE          NONE       NO
         1 SOE        DEDICATED mootdb_prod          JDBC Thin Client     ACTIVE   NONE          NONE       NO
         1 SOE        DEDICATED mootdb_prod          JDBC Thin Client     ACTIVE   NONE          NONE       NO
         1 SOE        DEDICATED mootdb_prod          JDBC Thin Client     ACTIVE   NONE          NONE       NO
         2 SOE        DEDICATED mootdb_prod          JDBC Thin Client     ACTIVE   NONE          NONE       NO
         2 SOE        DEDICATED mootdb_prod          JDBC Thin Client     ACTIVE   NONE          NONE       NO
         2 SOE        DEDICATED mootdb_prod          JDBC Thin Client     ACTIVE   NONE          NONE       NO
         2 SOE        DEDICATED mootdb_prod          JDBC Thin Client     ACTIVE   NONE          NONE       NO
         2 SOE        DEDICATED mootdb_prod          JDBC Thin Client     ACTIVE   NONE          NONE       NO
         2 SOE        DEDICATED mootdb_prod          JDBC Thin Client     ACTIVE   NONE          NONE       NO
         2 SOE        DEDICATED mootdb_prod          JDBC Thin Client     ACTIVE   NONE          NONE       NO
         2 SOE        DEDICATED mootdb_prod          JDBC Thin Client     ACTIVE   NONE          NONE       NO
         2 SOE        DEDICATED mootdb_prod          JDBC Thin Client     ACTIVE   NONE          NONE       NO

The only session using the TAF above is a session created manually from sqlplus (failover_type column). I'm using the same tnsnames alias in all sessions.

Why is this happening. Is there some requirement in the application side as well for it work correctly?

Answer 1

The output shows that your sessions use the "Thin" driver (JDBC Thin Client), which is incapable of using TAF.

Transparent Application Failover

Transparent Application Failover (TAF) is a feature of the Java Database Connectivity (JDBC) Oracle Call Interface (OCI) driver.

Sometimes the JDBC OCI driver is also called as the "Thick" driver.

Here is a blog series about this topic:

https://blog.yannickjaquier.com/oracle/jdbc-client-high-availability-features-part-1.html

Part 2 is about TAF:

https://blog.yannickjaquier.com/oracle/jdbc-failover-highly-available-part-2.html

Make sure you configure swingbench to use oci driver type. It has the -dt oci commandline option for that. Also make sure you use a proper connection string with the failover options and addresses.