Hi, I'm working on a new pl/java prototype that I hope will become production quality some time in the future. Before my project gets to far, I'd like to gather some input from other users. I've taken a slightly different approach than what seems to be the case for other attempts that I've managed to dig up. Here's some highlights in my approach:
1. A new Java VM is spawned for each connection. I know that this will give a performance hit when a new connection is created. The alternative however, implies that all calls becomes inter-process calls which I think is a much worse scenario. Especially since most modern environments today has some kind of connection pooling. Another reason is that the connections represents sessions and those sessions gets a very natural isolation using separate VM's. A third reason is that the "current connection" would become unavailable in a remote process (see #5).
Maybe on-demand might be better - if the particular backend doesn't need it why incur the overhead?
2. There's no actual Java code in the body of a function. Simply a reference to a static method. My reasoning is that when writing (and debugging) java, you want to use your favorite IDE. Mixing Java with SQL just gets messy.
Perhaps an example or two might help me understand better how this would work.
3. As opposed to the Tcl, Python, and Perl, that for obvious reasons uses strings, my pl/java will use native types wherever possible. A flag can be added to the function definition if real objects are preferred instead of primitives (motivated by the fact that the primitives cannot reflect NULL values).
4. The code is actually written using JNI and C++ but without any templates, no &-style object references, no operator overloads, external class libraries etc. I use C++ simply to get better quality, readability and structure on the code.
Other pl* (perl, python, tcl) languages have vanilla C glue code. Might be better to stick to this. If you aren't using advanced C++ features that shouldn't be too hard - well structured C can be just as readable as well structured C++. At the very lowest level, about the only things C++ buys you are the ability to declare variables in arbitrary places, and // style comments.
5. I plan to write a JDBC layer using JNI on top of the SPI calls to enable JDBC functionality on the current connection. Some things will be limited (begin/commit etc. will not be possible to do here for instance).
Again. examples would help me understand better.
Is there a web page for your project?
cheers
andrew
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