Suppose a company wishes to build a graph database using their own innovative graph index data structure. They nevertheless need to implement core relational algebra, core data types, and core built-in functions (+, CASE, SUM, SUBSTRING). And they want to implement these on a memory-efficient data structure (tens of thousands of rows, stored column-oriented, per memory block). This is a massive effort.
With Calcite+Gandiva+Arrow they just need to create a sequence of relational operators (using RelBuilder, say) and efficient machine code is generated. They can then start adding their own data types, built-in functions, and relational operators, using the same architecture.
> On Jun 22, 2018, at 11:33 AM, Xiening Dai <xndai.git@xxxxxxxx> wrote:
> I was in a talk regarding Gandiva yesterday. Impressive work!
> But I am not sure why Calcite would like to integrate with it. To me Gandiva is on execution side, in which scenarios a query planner would need a arrow engine? I read the original Jira about implementing file enumerator, but the intent is still not clear to me. Would appreciate if you can elaborate. Thanks.
>> On Jun 22, 2018, at 11:20 AM, Julian Hyde <jhyde@xxxxxxxxxx> wrote:
>> There is a discussion on dev@arrow about Gandiva, a kernel for Arrow.
>> I think it would be an interesting library on which to build our Arrow engine. (Without a kernel, Arrow is just a data format, but with Gandiva it becomes an engine upon which we can implement all relational operations, albeit on a multi-threaded single node. Potentially this approach can process each row in a few machine cycles, i.e. billions of records per second. Therefore single-node would be sufficient for many queries.)
>> Masayuki Takahashi has started to develop an Arrow adapter for Calcite, but a lot of work remains to implement all SQL built-in functions and basic relational operators. Building on top of Gandiva we could save a lot of this effort.
>>  https://lists.apache.org/thread.html/f099b3d1e2aaf9803c5c756f872a594baf17e9f25974e3496c9706d9@%3Cdev.arrow.apache.org%3E <https://lists.apache.org/thread.html/f099b3d1e2aaf9803c5c756f872a594baf17e9f25974e3496c9706d9@%3Cdev.arrow.apache.org%3E>
>>  https://issues.apache.org/jira/browse/CALCITE-2173 <https://issues.apache.org/jira/browse/CALCITE-2173>