CallableStatements weren't in Postgres as of the last time I
checked, version 7.1.
The JDBC specification has lots of goodies in it, such as
examining a server's metadata and sending cursors backwards and
forwards over result sets. However, from the perspective of a
Java programmer, CallableStatements are essential tools for
communicating with a database server.
Without the benefit of CallableStatements, all efforts at
efficiency are wasted. The hallmark of any robust system is
distributed processing, which requires invoking stored procedures
on foreign machines. Doing so through CallableStatements would
(a) accomplish work and (b) retrieve a result code in one logical
network transmission. Without CallableStatements, retrieving the
result code not only requires more programming infrastructure,
but also taxes the application at runtime as the Java application
tries to discover what the result of the stored procedure was.
This method requires an additional deletion to purge the logged
result code record, lest the log grow, slowing searches.
Therefore, we are looking at considerably more processing done, 2
or 3 transmissions, where 1 should suffice.
Consequently, I would hope that CallableStatements are recognized
as a very important part of the JDBC puzzle.