Exception handling

Exception handling

You can catch and handle an exception in the PostgreSQL back-end just like any other exception. The back-end ErrorData structure is exposed as a property in a ServerException class derived from java.sql.SQLException, and the Java try/catch mechanism is synchronized with the back-end mechanism.

Note: for several reasons (see Thoughts on logging for background), referring to ServerException and ErrorData from your code is not currently recommended, and in the future may become impossible. An improved mechanism is expected in a future release. Until then, using only the standard Java API of java.sql.SQLException and its standard attributes (such as SQLState) is recommended wherever possible.

PL/Java will always catch exceptions that you don't. They will cause a PostgreSQL error and the message is logged using the PostgreSQL logging utilities. The stack trace of the exception will also be printed if the PostgreSQL configuration parameter log_min_messages is set to DEBUG1 or lower.

Important Note:

You will not be able to continue executing back-end functions until your function has returned and the error has been propagated when the back-end has generated an exception unless you have used a save-point. When a save-point is rolled back, the exceptional condition is reset and execution can continue.