The generated code is readable and debuggable. https://calcite.apache.org/docs/howto.html#debugging-generated-classes-in-intellij The more data you have, the more benefits you get from Codegen.
On 2020/05/13 19:19:13, Rui Wang <amaliu...@apache.org> wrote: > Based on my past experience in distributed computing, there is a difference > between a compilation time that generates java code and then compiles java > code into bytecode, and a runtime that runs bytecode by JVM. > > The compilation will take time, but the runtime shouldn't be slower due to > a good generation of bytecode. It works for distributed computation. For > example, the query complies in your local machine, slower compilation time > (a few more minutes?) is ok, and then the bytecode will run on multiple > workers which can execute bytecode directly (so efficient). I don't have a > benchmark to show the difference between running java code and executing > bytecode, but in Apache Beam, after we switched to the dynamic code > generation, we didn't see a performance regression. > > > However I don't have enough experience on if single machine SQL engine can > benefit from this concept. > > > -Rui > > On Wed, May 13, 2020 at 11:54 AM 徐泷泽 <15258826...@qq.com> wrote: > > > Hi buddies ! > > Our team is working on developing a mulit data source sql engine use > > Calcite.But something confuse us, why calcite generate Java code > > dynamicly on SQL query, it seen have performance issues in my opinion. > > And building dynamic code object is very hard，the code is unreadable and > > hard to understood, futhermore we can not debug it. > > > > > > i wander why it was designed like that, what advantage of that .we > > search on internet, > > but nobody can realy explain it(may be we not goot at search, and poor > > english). > > so anybody can tell me the history of this, or give us some article. > > > > > > applogize for my poor english, hope you know what i'm taking aboult. > > thank you very very very much ! >
