handle cache key types (#11369)

Signed-off-by: Harshit Gangal <harshit@planetscale.com>

Signed-off-by: Harshit Gangal <harshit@planetscale.com>

go/vt/vttablet/endtoend/settings_test.go

@@ -421,3 +421,26 @@ func TestInfiniteSessions(t *testing.T) {
 			client.Commit())
 	}
 }
+
+func TestSetQueriesMultipleWays(t *testing.T) {
+	client := framework.NewClient()
+	defer client.Release()
+	_, err := client.ReserveExecute("select 1", []string{"set sql_safe_updates = 1"}, nil)
+	require.NoError(t, err)
+
+	_, err = client.Execute("set sql_safe_updates = 1", nil)
+	require.NoError(t, err)
+
+	framework.Server.Config().EnableSettingsPool = true
+	defer func() {
+		framework.Server.Config().EnableSettingsPool = false
+	}()
+
+	client2 := framework.NewClient()
+	_, err = client2.ReserveExecute("select 1", []string{"set sql_safe_updates = 1"}, nil)
+	require.NoError(t, err)
+
+	// this should not panic.
+	_, err = client.Execute("set sql_safe_updates = 1", nil)
+	require.NoError(t, err)
+}

go/vt/vttablet/tabletserver/query_engine.go

@@ -436,15 +436,25 @@ func (qe *QueryEngine) schemaChanged(tables map[string]*schema.Table, created, a
 
 // getQuery fetches the plan and makes it the most recent.
 func (qe *QueryEngine) getQuery(sql string) *TabletPlan {
-	if cacheResult, ok := qe.plans.Get(sql); ok {
-		return cacheResult.(*TabletPlan)
+	cacheResult, ok := qe.plans.Get(sql)
+	if !ok {
+		return nil
+	}
+	plan, ok := cacheResult.(*TabletPlan)
+	if ok {
+		return plan
 	}
 	return nil
 }
 
 func (qe *QueryEngine) getConnSetting(key string) *pools.Setting {
-	if cacheResult, ok := qe.plans.Get(key); ok {
-		return cacheResult.(*pools.Setting)
+	cacheResult, ok := qe.plans.Get(key)
+	if !ok {
+		return nil
+	}
+	plan, ok := cacheResult.(*pools.Setting)
+	if ok {
+		return plan
 	}
 	return nil
 }