app/vminsert/prompush: limit memory usage by pushing promscrape data in smaller blocks

app/vminsert/prompush/push.go

@@ -17,22 +17,38 @@ var (
 	rowsPerInsert = metrics.NewHistogram(`vm_rows_per_insert{type="promscrape"}`)
 )
 
-// Push pushes wr to to storage.
+const maxRowsPerBlock = 10000
+
+// Push pushes wr to storage.
 func Push(wr *prompbmarshal.WriteRequest) {
 	ctx := getPushCtx()
 	defer putPushCtx(ctx)
 
-	timeseries := wr.Timeseries
+	tss := wr.Timeseries
+	for len(tss) > 0 {
+		// Process big tss in smaller blocks in order to reduce maxmimum memory usage
+		tssBlock := tss
+		if len(tssBlock) > maxRowsPerBlock {
+			tssBlock = tss[:maxRowsPerBlock]
+			tss = tss[maxRowsPerBlock:]
+		} else {
+			tss = nil
+		}
+		ctx.push(tssBlock)
+	}
+}
+
+func (ctx *pushCtx) push(tss []prompbmarshal.TimeSeries) {
 	rowsLen := 0
-	for i := range timeseries {
-		rowsLen += len(timeseries[i].Samples)
+	for i := range tss {
+		rowsLen += len(tss[i].Samples)
 	}
 	ic := &ctx.Common
 	ic.Reset(rowsLen)
 	rowsTotal := 0
 	labels := ctx.labels[:0]
-	for i := range timeseries {
-		ts := &timeseries[i]
+	for i := range tss {
+		ts := &tss[i]
 		labels = labels[:0]
 		for j := range ts.Labels {
 			label := &ts.Labels[j]