Reuse Histogram objects in tsdb-chunks and tsdb-print-chunk tools (#7260

)

Signed-off-by: Yuri Nikolic <[email protected]>

tools/tsdb-chunks/main.go

@@ -73,6 +73,7 @@ func printChunksFile(filename string, printSamples bool) error {
 	var (
 		h  *histogram.Histogram      // reused in iteration as we just dump the value and move on
 		fh *histogram.FloatHistogram // reused in iteration as we just dump the value and move on
+		ts int64                     // we declare ts here to prevent shadowing of h and fh within the loop
 	)
 	for c, err := nextChunk(cix, file); err == nil; c, err = nextChunk(cix, file) {
 		if printSamples {
@@ -94,7 +95,7 @@ func printChunksFile(filename string, printSamples bool) error {
 
 					fmt.Printf("Chunk #%d, sample #%d: ts: %d (%s), val: %g\n", cix, six, ts, formatTimestamp(ts), val)
 				case chunkenc.ValHistogram:
-					ts, h := it.AtHistogram(h)
+					ts, h = it.AtHistogram(h)
 					if ts < minTS {
 						minTS = ts
 					}
@@ -104,7 +105,7 @@ func printChunksFile(filename string, printSamples bool) error {
 
 					fmt.Printf("Chunk #%d, sample #%d: ts: %d (%s), val: %s\n", cix, six, ts, formatTimestamp(ts), h.String())
 				case chunkenc.ValFloatHistogram:
-					ts, fh := it.AtFloatHistogram(fh)
+					ts, fh = it.AtFloatHistogram(fh)
 					if ts < minTS {
 						minTS = ts
 					}

tools/tsdb-print-chunk/main.go

@@ -65,17 +65,18 @@ func printChunks(blockDir string, chunkRefs []string) {
 		var (
 			h  *histogram.Histogram      // reused in iteration as we just dump the value and move on
 			fh *histogram.FloatHistogram // reused in iteration as we just dump the value and move on
+			ts int64                     // we declare ts here to prevent shadowing of h and fh within the loop
 		)
 		for valType := it.Next(); valType != chunkenc.ValNone; valType = it.Next() {
 			switch valType {
 			case chunkenc.ValFloat:
 				ts, v := it.At()
 				fmt.Printf("%g\t%d (%s)\n", v, ts, timestamp.Time(ts).UTC().Format(time.RFC3339Nano))
 			case chunkenc.ValHistogram:
-				ts, h := it.AtHistogram(h)
+				ts, h = it.AtHistogram(h)
 				fmt.Printf("%s\t%d (%s)\n", h.String(), ts, timestamp.Time(ts).UTC().Format(time.RFC3339Nano))
 			case chunkenc.ValFloatHistogram:
-				ts, fh := it.AtFloatHistogram(fh)
+				ts, fh = it.AtFloatHistogram(fh)
 				fmt.Printf("%s\t%d (%s)\n", fh.String(), ts, timestamp.Time(ts).UTC().Format(time.RFC3339Nano))
 			default:
 				fmt.Printf("skipping unsupported value type %v\n", valType)