[FEATURE] Calcite Engine Framework: General function (UDF/UDAF) framework

[LantaoJin]

Is your feature request related to a problem?
Framework work of the development feature of Calcite Engine.

What solution would you like?
General function (UDF/UDAF) framework: Built-in UDF/UDAF, Custom UDF/UDAF

[andy-k-improving]

Question mainly on the registration part, currently we have issue similar to #811 which prevent us to implement Storage engine specific function (Ex: OpenSearch) in concise manner and without workaround.

This is not a must for Calcite UDF integration, but definitely would be great and we should take this consideration when working on this item.

[LantaoJin]

Question mainly on the registration part, currently we have issue similar to #811 which prevent us to implement Storage engine specific function (Ex: OpenSearch) in concise manner and without workaround.

This is not a must for Calcite UDF integration, but definitely would be great and we should take this consideration when working on this item.

Thanks for the extra context. Yes, register UDF dynamically should be considered in design. BTW, in first stage about Calcite integration, we will implement it in OpenSearch storage engine only. But we should keep the interface easy to extend when we move to next stage (supporting more storage engines).