alamb opened a new issue, #9554: URL: https://github.com/apache/arrow-datafusion/issues/9554
### Is your feature request related to a problem or challenge? As part of https://github.com/apache/arrow-datafusion/issues/462, @matthewgapp implemented support for recursive Common Table Expressions (aka Recursive CTEs) Here is an example of such a query: https://github.com/apache/arrow-datafusion/blob/4cd3c433004a7a6825643d6b3911db720efe5f76/datafusion/sqllogictest/test_files/cte.slt#L44-L68 At the moment, to use recursive CTEs you must enable a config option: ```sql set datafusion.execution.enable_recursive_ctes = true; ``` ### Describe the solution you'd like I would like recursive CTEs to be enabled by default (and thus useable without a config option) The only reason I know of at the moment that they are NOT enabled by default is because they might buffer an infinite amount of data (and thus exceed the total memory available to DataFusion) ### Describe alternatives you've considered I think the basic idea would be to 1. Extend `RecursiveQueryExec` with a `MemoryReservation` 2. Track the memory of any buffered batches, erroring if they can not be buffered 3. Write a test in `memory_limit.rs` showing the limit being hit: https://github.com/apache/arrow-datafusion/blob/main/datafusion/core/tests/memory_limit.rs 4. Change the default value of The main PR that added this feature was https://github.com/apache/arrow-datafusion/pull/8840 ### Additional context _No response_ -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: [email protected] For queries about this service, please contact Infrastructure at: [email protected]
