Push down everything but in_keyrange

Signed-off-by: Matt Lord <mattalord@gmail.com>

go/vt/vttablet/tabletserver/vstreamer/planbuilder.go

@@ -61,7 +61,7 @@ type Plan struct {
 	// Predicates in the Filter query that we can push down to
 	// MySQL to reduce the returned rows we need to filter.
 	// This will contain any valid expressions in the Filter's
-	// WHERE clause with the exception of the in_keyspace()
+	// WHERE clause with the exception of the in_keyrange()
 	// function which is a filter that must be applied by the
 	// vstreamer (it's not a valid MySQL function).
 	whereExprsToPushDown []sqlparser.Expr
@@ -613,9 +613,13 @@ func (plan *Plan) analyzeWhere(vschema *localVSchema, where *sqlparser.Where) er
 			// Add it to the expressions that get pushed down to mysqld.
 			log.Errorf("DEBUG: adding to list of pushdown expressions: %v", sqlparser.String(expr))
 			plan.whereExprsToPushDown = append(plan.whereExprsToPushDown, expr)
-			// StrVal is varbinary, we do not support varchar since we would have to implement all collation types
 			if val.Type != sqlparser.IntVal && val.Type != sqlparser.StrVal {
-				return fmt.Errorf("unexpected: %v", sqlparser.String(expr))
+				// StrVal is varbinary, we do not support varchar filtering in
+				// vstreamer since we would have to do so using the correct
+				// collation. So we ONLY push it down to mysqld.
+				// TODO: now that we have MySQL compatible collation support
+				// we could add this support to vstreamer as well.
+				continue
 			}
 			pv, err := evalengine.Translate(val, &evalengine.Config{
 				Collation:   plan.env.CollationEnv().DefaultConnectionCharset(),
@@ -635,11 +639,14 @@ func (plan *Plan) analyzeWhere(vschema *localVSchema, where *sqlparser.Where) er
 				Value:  resolved.Value(plan.env.CollationEnv().DefaultConnectionCharset()),
 			})
 		case *sqlparser.FuncExpr:
-			if !expr.Name.EqualString("in_keyrange") {
-				return fmt.Errorf("unsupported constraint: %v", sqlparser.String(expr))
-			}
-			if err := plan.analyzeInKeyRange(vschema, expr.Exprs); err != nil {
-				return err
+			if expr.Name.EqualString("in_keyrange") {
+				if err := plan.analyzeInKeyRange(vschema, expr.Exprs); err != nil {
+					return err
+				}
+			} else {
+				log.Errorf("DEBUG: adding to list of pushdown expressions: %v", sqlparser.String(expr))
+				// Add it to the expressions that get pushed down to mysqld.
+				plan.whereExprsToPushDown = append(plan.whereExprsToPushDown, expr)
 			}
 		case *sqlparser.IsExpr: // Needed for CreateLookupVindex with ignore_nulls
 			if expr.Right != sqlparser.IsNotNullOp {
@@ -660,6 +667,7 @@ func (plan *Plan) analyzeWhere(vschema *localVSchema, where *sqlparser.Where) er
 				Opcode: IsNotNull,
 				ColNum: colnum,
 			})
+			log.Errorf("DEBUG: adding to list of pushdown expressions: %v", sqlparser.String(expr))
 			// Add it to the expressions that get pushed down to mysqld.
 			plan.whereExprsToPushDown = append(plan.whereExprsToPushDown, expr)
 		default: