WIP sql ast

[domoritz]

Fixes #377

WIP until raco side is implemented

[domoritz]

Not really what I was hoping to do do today but certainly useful. Ready for review.

@7andrew7 This changed the interface for table scans and allows you to push work down into the database. Hence, raco has to be adapted. We can have a chat about the format. At the moment, I expect DbQueryScan operators to be like:

{
  "query": {
    "selectExpressions": [{
      "rootExpressionOperator": {
        "type": "COLUMN",
        "columnIdx": 0,
        "relationKey": {
          "userName": "public",
          "relationName": "TwitterK",
          "programName": "adhoc"
        }
      },
      "outputName": "x"
    }]
  },
  "opId": "V1",
  "opType": "DbQueryScan",
  "opName": "MyriaScan(public:adhoc:TwitterK)"
}

There is also support for where clauses and order by. See the code for a reference.

[coveralls]

Coverage increased (+0.46%) when pulling 878308b on domoritz-sql-ast into 1ac65d4 on master.

[dhalperi]

No sense merging these changes until the raco changes are completed, right? No guarantee this is the right java-side encoding until both work together...

[domoritz]

I agree.

[7andrew7]

I'll take a crack at raco side, but it probably won't be this week.

[domoritz]

One thing that is missing and should probably be added is aggregation. My plan is to add another expression operator and automatically generate the group by clause. Will tackle this some time next week. It should not affect the JSON api, though.

[dhalperi]

Another way to go about this, btw, would be to try and actually use the
given query fragment to generate a DbQueryScan. Just a (wacky) thought.

---

Daniel Halperin
Director of Research for Scalable Analytics
eScience Institute
University of Washington

On Fri, May 23, 2014 at 12:19 AM, Dominik Moritz
notifications@github.comwrote:

One thing that is missing and should probably be added is aggregation. My
plan is to add another expression operator and automatically generate the
group by clause. Will tackle this some time next week. It should not affect
the JSON api, though.

—
Reply to this email directly or view it on GitHubhttps://github.com//pull/518#issuecomment-43978290
.

[domoritz]

Another way to go about this, btw, would be to try and actually use the
given query fragment to generate a DbQueryScan. Just a (wacky) thought.

I don't get it. Do you mean not using any of the code that I've written and just take the query plan and generate a query from that? Sounds possible but won't get us very far since pg and myria have non overlapping features.

[dhalperi]

Closed via discussion today. Possibly reexplore when @domoritz is back.