While working on ADBC/Flight SQL integration, I noticed the example Flight SQL server implementations don't fully handle CommandPreparedStatementQuery [1]. This message is used to execute a result set-returning prepared statement, and is also used to bind parameters before execution.
Right now, the example servers ignore all but the last row of parameters given; so while you can provide multiple parameter sets to be executed at once, it's not implemented. Based on discussion in [2] the problem is whether we want to model multiple result sets, or just assume all the result sets can be concatenated into one. (Or, we could explicitly require only a single row of parameters.) Which would be the expected/most desirable behavior? Note ADBC faces a similar problem; so far the API assumes all result sets can be concatenated into one in this case [3] (this mimics behavior in R's DBI [4]). [1]: https://github.com/apache/arrow/blob/apache-arrow-8.0.0/format/FlightSql.proto#L1488-L1511 [2]: https://issues.apache.org/jira/browse/ARROW-17199 [3]: https://github.com/apache/arrow-adbc/blob/41daacca08db041b52b458503e713a80528ba65a/adbc.h#L667-L679 [4]: https://dbi.r-dbi.org/reference/dbbind#specification-1 -David
