Pranav, Please subscribe to this list. You have asked several questions, received replies, not acknowledged those replies, and asked further questions. Also, since you are not subscribed, each email you post has to go through manual moderation.
Julian > On Aug 5, 2022, at 9:38 AM, Pranav Deshpande <deshpande.v.pra...@gmail.com> > wrote: > > Dear Apache Calcite Team, > I have 2 questions. > > --------------------------------- > 1. > > There are plenty of examples on how to push down projects and filters into > the leaf nodes (tablescans). > > However, I could not find any examples to push down joins to TableScans (or > joins+filters+projects etc.) [this is helpful for data federation I think]. > > On the mailing list, many folks are suggesting that I use Drill. However, > the purpose of my exercise is to gain knowledge about DBMS and Query > processing etc. > > I tried debugging open source engines that use Calcite (Drill, Druid, Trino > etc.) but was completely lost. > > Any examples/pointers/guidance around the same would be appreciated. > Example, pushing down a join with a filter to a DBMS(consider jdbc > msql etc.) > > ------------------------------------- > 2. > > The 2nd question I have is regarding conventions and different DBMS. The > cluster has a method to replace the trait convention(Bindable,JDBC etc.), > and then we optimize and get the physical plan. > > But imagine I have both the MYSQL JDBC convnction and a cassandra > convention and some user is trying to query both tables. > > Something like "SELECT users.username, specialdata.country from > cassandraDB.user join mysqlDB.specialdata ON users.id=specialdata.userid" > > Now, how will calcite do the optimization here? The planner is not > accepting 2 different conventions. > > Thanks & Regards, > Pranav
