From 0fbfa8c245a5975e072772f19cd2434a6bd2a903 Mon Sep 17 00:00:00 2001
From: Aliaksandr Valialkin <valyala@victoriametrics.com>
Date: Mon, 31 Jan 2022 22:45:56 +0200
Subject: [PATCH] lib/storage: avoid allocations of tsidPrev on every
 blockStreamReader.NextBlock() call

This is a follow-up for 00b7c97d2a9e27693d9156803fdcb485b262eddd

Updates https://github.com/VictoriaMetrics/VictoriaMetrics/issues/2082
---
 lib/storage/block_stream_reader.go | 11 ++++++++---
 1 file changed, 8 insertions(+), 3 deletions(-)

diff --git a/lib/storage/block_stream_reader.go b/lib/storage/block_stream_reader.go
index 6398adf226..9d9361c47d 100644
--- a/lib/storage/block_stream_reader.go
+++ b/lib/storage/block_stream_reader.go
@@ -18,6 +18,11 @@ type blockStreamReader struct {
 	// Currently active block.
 	Block Block
 
+	// Contains TSID for the previous block.
+	// This field is needed for checking that TSIDs
+	// increase over time when reading blocks.
+	tsidPrev TSID
+
 	// Filesystem path to the stream reader.
 	//
 	// Is empty for inmemory stream readers.
@@ -213,12 +218,12 @@ func (bsr *blockStreamReader) NextBlock() bool {
 	if bsr.err != nil {
 		return false
 	}
-	tsidPrev := bsr.Block.bh.TSID
+	bsr.tsidPrev = bsr.Block.bh.TSID
 	bsr.Block.Reset()
 	err := bsr.readBlock()
 	if err == nil {
-		if bsr.Block.bh.TSID.Less(&tsidPrev) {
-			bsr.err = fmt.Errorf("possible data corruption: the next TSID=%v is smaller than the previous TSID=%v", &bsr.Block.bh.TSID, &tsidPrev)
+		if bsr.Block.bh.TSID.Less(&bsr.tsidPrev) {
+			bsr.err = fmt.Errorf("possible data corruption: the next TSID=%v is smaller than the previous TSID=%v", &bsr.Block.bh.TSID, &bsr.tsidPrev)
 			return false
 		}
 		if bsr.Block.bh.RowsCount == 0 {