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From Lisen Mu <imm...@gmail.com>
Subject Re: Question about optiq
Date Fri, 03 May 2013 08:53:38 GMT
Julian,

Thanks for the detailed explanation.

On Tue, Apr 30, 2013 at 4:29 PM, Julian Hyde <julianhyde@gmail.com> wrote:

> Optiq just has basic support for reading from JDBC sources. Full support
> would be to take a tree of relational algebra operators and push as many of
> them down into a SQL query. Right now there's only one operator, JdbcTable,
> and as you noted it hard-codes the schema name as "foodmart". (That
> hard-coding would be easy to solve by adding another field to either
> JdbcTable or JdbcSchema.)
>
> JdbcTable is serving its purpose right now, because it allows us to read
> from a JDBC database into memory, and then execute queries on those
> in-memory tables. (See CloneSchema.) I've developed a set of operators that
> query in-memory tables using Java iterators (see the inner classes of
> JavaRules). These helped me to debug the planning process, and to start
> building in-memory materialized views, which are two of my key goals for
> Optiq.
>
> When we need to, we can build out the JDBC adapter incrementally by adding
> operators such as JdbcFilter and JdbcJoin; a JDBC calling-convention; and
> an operator that "converts" from JDBC calling-convention to the
> "enumerable" convention used by JavaRules by generating a SQL query from
> the tree of JdbcXxx operators under it and executing it using JDBC.
>
> Optiq is designed to support a wide variety of back-ends, but each one
> takes work, so there aren't that many right now. In addition to JDBC, there
> is a Splunk adapter, which supports push down of project and filter [
> https://github.com/julianhyde/optiq-splunk ]; there is Lingual, which
> supports Cascading [ https://github.com/Cascading/lingual ]; and though
> not really a "back end", there is the "Enumerable" adapter in JavaRules I
> mentioned earlier, which can run queries against any Java collection or
> iterator.
>
> LinqFrontJdbcBackTest isn't a bad test to run. You might also try
> JdbcTest.testCloneQueries(); this loads JDBC tables into memory and runs
> various SQL statements on the in-memory tables. To run these tests you need
> to load the FoodMart data set into a database such as MySQL first.
>
> Julian
>
> PS I've CC:ed optiq-dev, and you're now on the list.
>
> On Apr 26, 2013, at 3:39 AM, Lisen Mu <immars@gmail.com> wrote:
>
> > Hi,
> >
> > Sorry to interrupt but I don't have access to post in optiq-dev for now
> so
> > I put it here.
> >
> > What's the current status of optiq jdbc backend impl? Seems there is some
> > hard coded info in JdbcTable.
> >
> > I'm looking into optiq to see the chance of using it in MySQLSE.
> >
> > It seems to me that I shall convert Drill scanpop into Linq4j Expressions
> > and submit it to Optiq instead of creating sql string myself, to avoid
> both
> > handcrafted sql string concating and sql parsing stage of optiq. And
> maybe
> > other SE in the future if Optiq can support more backend.
> >
> > But when I run LinqFrontJdbcBackTest(Is that the right test to run?) I
> > traced into JdbcTable which appears to be WIP. If jdbc backend is not
> > available, is there any other suggestion with optiq?
> >
> > Thanks,
>
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