Hi all, I am using Groovy embedded into an application which runs user-provided scripts. I see a significant parsing performance issue when the compiler is configured to add ~30 automatic imports via an ImportCustomizer, but I can't figure out why it is happening.
For various unrelated reasons, we segregate individual user scripts by creating a new GroovyClassLoader for each one and parsing each script in its own context. (These classloaders all chain to a single parent Groovy classloader that contains some shared functionality.) With the scripts segregated like this, I noticed that even an empty script takes 300+ ms to parse, which seems excessive. If I remove the automatic imports, the parse takes <10 ms instead. But I also found something bizarre in how the CompilerConfiguration seems to influence the parse time. I am 99% sure that the parsed class is not cached, since I turned off all of those options and I also stepped into the parse() function to confirm that it was walking through all of the phases. Could it be that the extra time is actually consumed by loading/resolving the imported classes, and not something Groovy is manipulating during the parse itself? That seems possible (and is potentially understandable, at least on the first invocation), except for one weirdness: The parse time problem appears tied to the specific instance of a CompilerConfiguration object being provided to the child classloader. For example, when creating the child classloader, if I supply the same CompilerConfiguration object that was provided to the parent classloader, the parse time suddenly get very fast! But if I instead construct a new CompilerConfiguration object for every script, the parse is very slow, even though the newly-constructed CC is identical to the previous one, and even though each script is still using its own separate classloader. What is going on (and how do I fix it)? Here is an example that you can run in groovysh that demonstrates the problem: http://pastebin.com/V1ijXPjC Here is the output: ===> true Showing slow parse time Parse time: 281 ms Parse time: 260 ms Parse time: 280 ms Parse time: 277 ms Parse time: 259 ms Parse time: 257 ms Parse time: 279 ms Parse time: 260 ms Parse time: 278 ms Parse time: 282 ms ===> null Showing fast parse time Parse time: 280 ms Parse time: 3 ms Parse time: 3 ms Parse time: 2 ms Parse time: 3 ms Parse time: 2 ms Parse time: 2 ms Parse time: 3 ms Parse time: 3 ms Parse time: 2 ms ===> null Thanks for any insight you can provide! - Scott
