This text is confusing in various ways, someone pointed out to me.
- We don't need to specifically reference crashes - mostly it's used as a workaround for performance problems. I think we should just say that it's used to work around any issues with Impala's runtime code generation.
- We should say clearly that most queries will run significantly slower with DISABLE_CODEGEN=true. The current text says this but it's hard to parse because of the implied double negative "do not run with the setting turned on", where "turned on" means "not disabled".
- It's still worth mentioning that some short-running queries may run faster with DISABLE_CODEGEN=true because of the overhead, but we shouldn't actively suggest users to tweak it in general. In 2.10+, the DISABLE_CODEGEN_ROWS_THRESHOLD optimisation automatically disables codegen for small queries to solve this automatically.