From b30db03f35651888e34ac101a06e25d27d15b476 Mon Sep 17 00:00:00 2001
From: Ganesh Vernekar <15064823+codesome@users.noreply.github.com>
Date: Fri, 1 Oct 2021 17:00:22 +0530
Subject: [PATCH] Cut v2.30.2 (#9426)

* Don't error on overlapping m-mapped chunks during WAL replay (#9381)

Signed-off-by: Ganesh Vernekar <ganeshvern@gmail.com>

* Reduce log level during WAL replay on overlapping m-map chunks (#9425)

Signed-off-by: Ganesh Vernekar <ganeshvern@gmail.com>

* Cut v2.30.2

Signed-off-by: Ganesh Vernekar <ganeshvern@gmail.com>
---
 CHANGELOG.md     |  4 ++++
 VERSION          |  2 +-
 tsdb/head_wal.go | 21 ++++++++++++++++-----
 3 files changed, 21 insertions(+), 6 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index d65c6bd99a..a226f51882 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,3 +1,7 @@
+## 2.30.2 / 2021-10-01
+
+* [BUGFIX] TSDB: Don't error on overlapping m-mapped chunks during WAL replay. #9381
+
 ## 2.30.1 / 2021-09-28
 
 * [ENHANCEMENT] Remote Write: Redact remote write URL when used for metric label. #9383
diff --git a/VERSION b/VERSION
index bcec02eeb9..0958964f67 100644
--- a/VERSION
+++ b/VERSION
@@ -1 +1 @@
-2.30.1
+2.30.2
diff --git a/tsdb/head_wal.go b/tsdb/head_wal.go
index 6a647dd852..ba98c2e467 100644
--- a/tsdb/head_wal.go
+++ b/tsdb/head_wal.go
@@ -46,6 +46,8 @@ func (h *Head) loadWAL(r *wal.Reader, multiRef map[uint64]uint64, mmappedChunks
 	// for error reporting.
 	var unknownRefs atomic.Uint64
 	var unknownExemplarRefs atomic.Uint64
+	// Track number of series records that had overlapping m-map chunks.
+	var mmapOverlappingChunks uint64
 
 	// Start workers that each process samples for a partition of the series ID space.
 	// They are connected through a ring of channels which ensures that all sample batches
@@ -241,8 +243,6 @@ Outer:
 				}
 
 				// Checking if the new m-mapped chunks overlap with the already existing ones.
-				// This should never happen, but we have a check anyway to detect any
-				// edge cases that we might have missed.
 				if len(mSeries.mmappedChunks) > 0 && len(mmc) > 0 {
 					if overlapsClosedInterval(
 						mSeries.mmappedChunks[0].minTime,
@@ -250,9 +250,17 @@ Outer:
 						mmc[0].minTime,
 						mmc[len(mmc)-1].maxTime,
 					) {
-						// The m-map chunks for the new series ref overlaps with old m-map chunks.
-						seriesCreationErr = errors.Errorf("overlapping m-mapped chunks for series %s", mSeries.lset.String())
-						break Outer
+						mmapOverlappingChunks++
+						level.Debug(h.logger).Log(
+							"msg", "M-mapped chunks overlap on a duplicate series record",
+							"series", mSeries.lset.String(),
+							"oldref", mSeries.ref,
+							"oldmint", mSeries.mmappedChunks[0].minTime,
+							"oldmaxt", mSeries.mmappedChunks[len(mSeries.mmappedChunks)-1].maxTime,
+							"newref", walSeries.Ref,
+							"newmint", mmc[0].minTime,
+							"newmaxt", mmc[len(mmc)-1].maxTime,
+						)
 					}
 				}
 
@@ -351,6 +359,9 @@ Outer:
 	if unknownRefs.Load() > 0 || unknownExemplarRefs.Load() > 0 {
 		level.Warn(h.logger).Log("msg", "Unknown series references", "samples", unknownRefs.Load(), "exemplars", unknownExemplarRefs.Load())
 	}
+	if mmapOverlappingChunks > 0 {
+		level.Info(h.logger).Log("msg", "Overlapping m-map chunks on duplicate series records", "count", mmapOverlappingChunks)
+	}
 	return nil
 }