mongo projection push down support left right comparisons

dataux · Nov 8, 2017 · ef7cd20 · ef7cd20
1 parent 7cc7f09
commit ef7cd20
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Showing 2 changed files with 32 additions and 64 deletions.
diff --git a/backends/mongo/mgo_test.go b/backends/mongo/mgo_test.go
@@ -585,62 +585,20 @@ func TestSelectAggsGroupBy(t *testing.T) {
 	})
 }
 */
-func TestSelectWhereEqual(t *testing.T) {
-	/*
-		data := struct {
-			Title   string
-			Count   int
-			Deleted bool
-			Updated time.Time
-		}{}
-		validateQuerySpec(t, tu.QuerySpec{
-			Sql: "select title, count, deleted, updated " +
-				"from article WHERE Count = 22;",
-			ExpectRowCt: 1,
-			ValidateRowData: func() {
-				//u.Infof("%v", data)
-				assert.True(t, data.Title != "", "%v", data)
-				//assert.True(t, data.Language == "Go", "%v", data)
-			},
-			RowData: &data,
-		})
-		// Test when we have compound where clause
-
-				validateQuerySpec(t, tu.QuerySpec{
-					Sql: "select `actor`, `repository.name`, `repository.stargazers_count`, `repository.language` " +
-						" from github_watch where " +
-						"`repository.language` == \"Go\" AND `repository.forks_count` > 1000;",
-					ExpectRowCt: 20,
-					ValidateRowData: func() {
-						//u.Infof("%v", data)
-						assert.True(t, data.Language == "Go", "%v", data)
-						assert.True(t, data.Stars > 1000, "must have filterd by forks: %v", data)
-						assert.True(t, data.Actor != "", "%v", data)
-					},
-					RowData: &data,
-				})
-
-			return
-			// TODO:   This isn't working yet bc the nested 3 where clauses
-			validateQuerySpec(t, tu.QuerySpec{
-				Sql: `
-				SELECT
-					actor, repository.name, repository.stargazers_count, repository.language
-				FROM github_watch
-				WHERE
-						repository.language = "Go"
-						AND repository.forks_count > 1000
-						AND repository.description NOT LIKE "docker";`,
-				ExpectRowCt: 20,
-				ValidateRowData: func() {
-					//u.Infof("%v", data)
-					assert.True(t, data.Language == "Go", "%v", data)
-					assert.True(t, data.Stars > 1000, "must have filterd by forks: %v", data)
-					assert.True(t, data.Actor != "", "%v", data)
-				},
-				RowData: &data,
-			})
-	*/
+func TestSelectWhereCompare(t *testing.T) {
+	data := struct {
+		Title   string
+		Count   int
+		Deleted bool
+	}{}
+	validateQuerySpec(t, tu.QuerySpec{
+		Sql:         "select title, count, deleted from article WHERE `author` != `title`",
+		ExpectRowCt: 4,
+		ValidateRowData: func() {
+			u.Infof("%v", data)
+		},
+		RowData: &data,
+	})
 }
 
 func TestSelectWhereLike(t *testing.T) {

diff --git a/backends/mongo/sql_to_mgo.go b/backends/mongo/sql_to_mgo.go
@@ -249,14 +249,17 @@ func (m *SqlToMgo) WalkExecSource(p *plan.Source) (exec.Task, error) {
 	return resultReader, nil
 }
 
-func (m *SqlToMgo) eval(arg expr.Node) (value.Value, bool) {
+// eval() returns
+//     value, isOk, isIdentity
+func (m *SqlToMgo) eval(arg expr.Node) (value.Value, bool, bool) {
 	switch arg := arg.(type) {
 	case *expr.NumberNode, *expr.StringNode:
-		return vm.Eval(nil, arg)
+		val, ok := vm.Eval(nil, arg)
+		return val, ok, false
 	case *expr.IdentityNode:
-		return value.NewStringValue(arg.Text), true
+		return value.NewStringValue(arg.Text), true, true
 	}
-	return nil, false
+	return nil, false, false
 }
 
 // Aggregations from the <select_list>
@@ -429,7 +432,7 @@ func (m *SqlToMgo) walkNode(cur expr.Node, q *bson.M) (value.Value, error) {
 //
 func (m *SqlToMgo) walkFilterTri(node *expr.TriNode, q *bson.M) (value.Value, error) {
 
-	arg1val, aok := m.eval(node.Args[0])
+	arg1val, aok, _ := m.eval(node.Args[0])
 	if !aok {
 		return nil, fmt.Errorf("Could not evaluate args: %v", node.String())
 	}
@@ -512,15 +515,22 @@ func (m *SqlToMgo) walkFilterBinary(node *expr.BinaryNode, q *bson.M) (value.Val
 		return nil, nil
 	}
 
-	lhval, lhok := m.eval(node.Args[0])
+	lhval, lhok, isLident := m.eval(node.Args[0])
+	rhval, rhok, isRident := m.eval(node.Args[1])
 	if !lhok {
-		return nil, fmt.Errorf("Could not evaluate args: %v", node.String())
+		return nil, fmt.Errorf("Could not evaluate left arg: %v", node.String())
 	}
-	rhval, rhok := m.eval(node.Args[1])
 	if !rhok {
 		u.Warnf("not ok: %v  l:%v  r:%v", node, lhval, rhval)
 		return nil, fmt.Errorf("could not evaluate: %v", node.String())
 	}
+	if isLident && isRident {
+		// comparison of left/right isn't mongos strong suit
+		// https://stackoverflow.com/questions/4442453/mongodb-query-condition-on-comparing-2-fields
+		// db.T.find( { $where : "this.Grade1 > this.Grade2" } );
+		*q = bson.M{"$where": fmt.Sprintf("this.%s %s this.%s", lhval.ToString(), node.Operator.V, rhval.ToString())}
+		return nil, nil
+	}
 	//u.Debugf("walkBinary: %v  l:%v  r:%v  %T  %T", node, lhval, rhval, lhval, rhval)
 	switch node.Operator.T {
 	case lex.TokenEqual, lex.TokenEqualEqual: