micronaut-projects
Hook to customize PreparedStatements before they are executed
Feature description
Some database drivers like Oracle's have useful features on PreparedStatement. One example is continuous query notification. Micronaut Data today can't be combined with these, because there's no way to get access to a PreparedStatement before it gets executed. It'd be useful to have a hook point which statements could be passed through after they're generated but before they're executed.
Two things:
- A pre-hook to edit the SQL before it's sent (useful in some advanced scenarios)
- Ability to call
OraclePreparedStatement.setDatabaseChangeRegistrationon the statement after it's been created.
Maybe, but that sounds like a lot more work? I've not seen it done before, how much effort would it be to write a DataSource that adds such features?
this is how micrometer observation does it https://github.com/micronaut-projects/micronaut-micrometer/tree/5.10.x/micrometer-observation-datasource/src/main/java/io/micronaut/micrometer/observation/datasource not sure of the quantity of work involved
It looks like it's using this library that makes intercepting and rewriting calls into the driver easy:
https://jdbc-observations.github.io/datasource-proxy/docs/current/user-guide/#about
I can try that. Is there a way to avoid collisions with micronaut-micrometer if multiple libraries want to proxy a DataSource? This code looks suspicious:
@Override
public int getOrder() {
// There is another listener in micronaut-tracing with HIGHEST_PRECEDENCE order
// so this is just to avoid beans with the same order
return Ordered.HIGHEST_PRECEDENCE + 1;
}
You can order yourself higher than the highest precedence.
It feels like this library could be wrapped by Micronaut SQL because it appears the proxying is somewhat immutable. I can add QueryExecutionListeners after the fact and that might be enough, but other stuff is set using a builder. It'd be convenient if there was only one proxy and the listeners were combined using the injector.
I'll experiment with that library.