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javaoracle-databasejdbctimeout

How is Oracle's JDBC query timeout implemented?

I was curious as to how the Oracle JDBC thin client implement query timeout. This can be set by calling java.sql.Statement's setQueryTimeout(int seconds) method.

Is this implemented in the driver itself on the client side? Is a new thread spawned and joined? Or does the JDBC driver simply send a parameter to Oracle, and then it enforces the timeout?

After the timeout is reached, which resources on the client and database are released, and which hang around? Does Oracle continue to run the query even though the client abandoned it or is it terminated? Is there still a cursor object on the client side?

Solution

  • Tanel Poder wrote an article on how a Cancel works through the OCI (Oracle Call Interface). I guess something similar is done for JDBC. If you are using the thick driver, through OCI, you could try tracing the session (through settings sqlnet.ora) and see what gets recorded.