feat: push down filter into the route when possible

Signed-off-by: Andres Taylor <andres@planetscale.com>
vitessio · Feb 10, 2022 · 22c7bca · 22c7bca
1 parent dfaf601
commit 22c7bca
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Showing 2 changed files with 23 additions and 26 deletions.
diff --git a/go/vt/vtgate/planbuilder/physical/route_planning.go b/go/vt/vtgate/planbuilder/physical/route_planning.go
@@ -85,10 +85,21 @@ func CreatePhysicalOperator(ctx *plancontext.PlanningContext, opTree abstract.Lo
 		if err != nil {
 			return nil, err
 		}
-		return &Filter{
-			Source:     src,
+
+		filter := &Filter{
 			Predicates: op.Predicates,
-		}, nil
+		}
+
+		if route, ok := src.(*Route); ok {
+			// let's push the filter into the route
+			filter.Source = route.Source
+			route.Source = filter
+			return route, nil
+		}
+
+		filter.Source = src
+
+		return filter, nil
 	default:
 		return nil, vterrors.Errorf(vtrpcpb.Code_INTERNAL, "invalid operator tree: %T", op)
 	}

diff --git a/go/vt/vtgate/planbuilder/testdata/filter_cases.txt b/go/vt/vtgate/planbuilder/testdata/filter_cases.txt
@@ -3915,29 +3915,15 @@ Gen4 plan same as above
   "QueryType": "SELECT",
   "Original": "select user.col from user_extra left outer join user on user_extra.user_id = user.id WHERE user.id IS NULL",
   "Instructions": {
-    "OperatorType": "SimpleProjection",
-    "Columns": [
-      1
-    ],
-    "Inputs": [
-      {
-        "OperatorType": "Filter",
-        "Predicate": "`user`.id is null",
-        "Inputs": [
-          {
-            "OperatorType": "Route",
-            "Variant": "Scatter",
-            "Keyspace": {
-              "Name": "user",
-              "Sharded": true
-            },
-            "FieldQuery": "select `user`.id, `user`.col from user_extra left join `user` on user_extra.user_id = `user`.id where 1 != 1",
-            "Query": "select `user`.id, `user`.col from user_extra left join `user` on user_extra.user_id = `user`.id",
-            "Table": "`user`, user_extra"
-          }
-        ]
-      }
-    ]
+    "OperatorType": "Route",
+    "Variant": "Scatter",
+    "Keyspace": {
+      "Name": "user",
+      "Sharded": true
+    },
+    "FieldQuery": "select `user`.col from user_extra left join `user` on user_extra.user_id = `user`.id where 1 != 1",
+    "Query": "select `user`.col from user_extra left join `user` on user_extra.user_id = `user`.id where `user`.id is null",
+    "Table": "`user`, user_extra"
   }
 }
 Gen4 plan same as above