From 4e4aa7cf2b94fb52dc8db494d7ee6c53b47cfdc3 Mon Sep 17 00:00:00 2001
From: Ben Ye <benye@amazon.com>
Date: Wed, 7 Jun 2023 12:55:52 -0700
Subject: [PATCH] index stats: fix chunk size calculation

Signed-off-by: Ben Ye <benye@amazon.com>
---
 pkg/block/index.go | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/pkg/block/index.go b/pkg/block/index.go
index 0aa7a74a75..afbc9653d9 100644
--- a/pkg/block/index.go
+++ b/pkg/block/index.go
@@ -293,7 +293,12 @@ func GatherIndexHealthStats(logger log.Logger, fn string, minTime, maxTime int64
 
 			// Approximate size.
 			if i < len(chks)-2 {
-				chunkSize.Add(int64(chks[i+1].Ref - c.Ref))
+				sgmIndex, chkStart := chunks.BlockChunkRef(c.Ref).Unpack()
+				sgmIndex2, chkStart2 := chunks.BlockChunkRef(chks[i+1].Ref).Unpack()
+				// Skip the case where two chunks are spread into 2 files.
+				if sgmIndex == sgmIndex2 {
+					chunkSize.Add(int64(chkStart2 - chkStart))
+				}
 			}
 
 			// Chunk vs the block ranges.