It sounds as if your requirements go beyond CALCITE-481. If so, please log a JIRA case.
> On Oct 10, 2016, at 8:52 AM, Chinmay Kolhatkar <chin...@apache.org> wrote: > > Thanks Julian. I think CALCITE-481 would be a good improvement. > > On Wed, Oct 5, 2016 at 11:02 PM, Julian Hyde <jhyde.apa...@gmail.com > <mailto:jhyde.apa...@gmail.com>> wrote: > >> What you are asking for is not currently possible but would be a very >> interesting, useful and powerful extension to Calcite. And in my opinion it >> fits well with the way with the way that Volcano/Cascades optimizers work. >> The idea would be for the optimizer to work on a forest (a set of trees >> with different roots, but shared leaves). >> >> It is related to https://issues.apache.org/jira/browse/CALCITE-481, which >> deals with trees that have a single root but store intermediate results so >> that they can be used more than once. I surmise that you are also very >> interested in maximizing the commonality between trees. >> >> The trickiest part is to get the cost model right. You need to account for >> a cost each time the work is done, not each time the result is used. Jesus >> researched this >> very topic, using integer linear programming (ILP) to incorporate these >> considerations into the cost model. >> >> Can you please create a JIRA case for it? Maybe Jesus can add some >> comments there. >> >> It is also related to Hive multi-table queries [1]. I have not seen a SQL >> syntax for multi-output queries. Maybe we can devise one. Or does someone >> know of one? >> >> And it presents challenges/opportunities for engines. Some engines can >> push to multiple consumers, or equivalently create a stream of tuples that >> can be read by multiple consumers, others can only persist an intermediate >> result that can be read by multiple consumers. Spark had their own version >> of this discussion when implementing multitable in Hive-Spark[2]. >> >> Julian >> >> [1] https://cwiki.apache.org/confluence/display/Hive/ >> GettingStarted#GettingStarted-MULTITABLEINSERT <https://cwiki.apache.org/ >> <https://cwiki.apache.org/> >> confluence/display/Hive/GettingStarted#GettingStarted-MULTITABLEINSERT> >> >> [2] https://issues.apache.org/jira/browse/SPARK-3622 >> <https://issues.apache.org/jira/browse/SPARK-3622> < >> https://issues.apache.org/jira/browse/SPARK-3622> >> >>> On Oct 4, 2016, at 9:23 AM, Chinmay Kolhatkar <chin...@datatorrent.com> >> wrote: >>> >>> Dear Community, >>> >>> I'm working on integration with Apache Apex and Apache Calcite >> (underlying >>> Apache Jira is: APEXMALHAR-1818). >>> >>> I have a question related to conversion from SQL to RelNode Tree. >>> >>> Is it possible that VolcanoPlanner can take multiple SQL statements as >>> input and return a unified RelNode Tree? >>> Example of above is as follows: >>> >>> SELECT COL1, COL2 FROM TABLE WHERE COL3 > 10; >>> SELECT COL1, COL2 FROM TABLE WHERE COL4 = 'abc'; >>> >>> Above 2 statements has a common path and hence can provide an unified >>> RelNode tree as follows: >>> >>> [Scan] -> [Project (COL1, COL2)] -> [Filter (COL4 = 'abc')] -> [Delta] >>> | >>> V >>> [Filter (COL3 > 10)] >>> | >>> v >>> [Delta] >>> >>> >>> Thanks, >>> Chinmay.
