Logging in PL/Java

PL/Java uses the standard java.util.logging.Logger Hence, you can write things like:

    "Time is " + new Date(System.currentTimeMillis()));

At present, the logger is hardwired to a handler that maps the state of the PostgreSQL configuration setting log_min_messages to a valid Logger level and that outputs all messages using the backend function ereport().

Importantly, Java’s Logger methods can quickly discard any message logged at a finer level than the one that was mapped from PostgreSQL’s setting at the time PL/Java was first used in the current session. Such messages never even get as far as ereport(), even if the PostgreSQL setting is changed later.

So, if expected messages from Java code are not showing up, be sure that the setting in PostgreSQL, at the time of PL/Java’s first use in the session, is fine enough that Java will not throw the messages away. Once PL/Java has started, the settings can be changed as desired and will control, in the usual way, what ereport does with the messages PL/Java delivers to it.

Through PL/Java 1.5.0, only the log_min_messages setting is used to set that Java cutoff level. Starting with 1.5.1, the cutoff level in Java is set (still only once at PL/Java startup) based on the finer of log_min_messages and client_min_messages.

The following mapping applies between the Logger levels and the PostgreSQL backend levels:

java.util.logging.LevelPostgreSQL level

See [[Thoughts on logging]] for likely future directions in this area.