Merge pull request #299 from ARCoder181105/perf/optimize-stops-for-route-polyline-allocs

aaronbrethorst · web-flow · commit 0be186276ae1 · 2026-02-05T16:36:09.000-08:00
Optimize memory allocation in stops-for-route polyline generation
diff --git a/internal/restapi/stops_for_route_handler.go b/internal/restapi/stops_for_route_handler.go
@@ -388,7 +388,8 @@ func processTripGroups(
 
 func generatePolylines(shapes []gtfsdb.GetShapesGroupedByTripHeadSignRow) []models.Polyline {
 	var polylines []models.Polyline
-	var coords [][]float64
+	// This prevents repeated memory re-allocation during the loop.
+	coords := make([][]float64, 0, len(shapes))
 	for _, shape := range shapes {
 		coords = append(coords, []float64{shape.Lat, shape.Lon})
 	}

Original file line number	Diff line number	Diff line change
`@@ -388,7 +388,8 @@ func processTripGroups(`
`388`	`388`
`389`	`389`	`func generatePolylines(shapes []gtfsdb.GetShapesGroupedByTripHeadSignRow) []models.Polyline {`
`390`	`390`	`var polylines []models.Polyline`
`391`		`- var coords [][]float64`
	`391`	`+ // This prevents repeated memory re-allocation during the loop.`
	`392`	`+ coords := make([][]float64, 0, len(shapes))`
`392`	`393`	`for _, shape := range shapes {`
`393`	`394`	`coords = append(coords, []float64{shape.Lat, shape.Lon})`
`394`	`395`	`}`