From da56cb6753a7302f45d26ad117cafe686aed8054 Mon Sep 17 00:00:00 2001
From: jiefenghuang <jiefeng@juicedata.io>
Date: Mon, 20 May 2024 10:57:37 +0800
Subject: [PATCH] disable disk cache state check when writeback enabled

Signed-off-by: jiefenghuang <jiefeng@juicedata.io>
---
 pkg/chunk/disk_cache.go       |  6 +++++-
 pkg/chunk/disk_cache_state.go | 18 ++++++++++++++----
 2 files changed, 19 insertions(+), 5 deletions(-)

diff --git a/pkg/chunk/disk_cache.go b/pkg/chunk/disk_cache.go
index acc91a5fb5cb..8ecf94c80303 100644
--- a/pkg/chunk/disk_cache.go
+++ b/pkg/chunk/disk_cache.go
@@ -130,7 +130,11 @@ func newCacheStore(m *cacheManagerMetrics, dir string, cacheSize int64, pendingP
 		opTs:          make(map[time.Duration]func() error),
 	}
 	c.stateLock = sync.Mutex{}
-	c.state = newDCState(dcNormal, c)
+	if config.Writeback {
+		c.state = newDCState(dcUnchanged, c)
+	} else {
+		c.state = newDCState(dcNormal, c)
+	}
 
 	c.createDir(c.dir)
 	br, fr := c.curFreeRatio()
diff --git a/pkg/chunk/disk_cache_state.go b/pkg/chunk/disk_cache_state.go
index d956c374a007..719647d01d3c 100644
--- a/pkg/chunk/disk_cache_state.go
+++ b/pkg/chunk/disk_cache_state.go
@@ -46,10 +46,11 @@ var (
 )
 
 var diskStateNames = map[int]string{
-	dcUnknown:  "unknown",
-	dcNormal:   "normal",
-	dcUnstable: "unstable",
-	dcDown:     "down",
+	dcUnknown:   "unknown",
+	dcNormal:    "normal",
+	dcUnstable:  "unstable",
+	dcDown:      "down",
+	dcUnchanged: "unchanged",
 }
 
 const (
@@ -57,6 +58,7 @@ const (
 	dcNormal
 	dcUnstable
 	dcDown
+	dcUnchanged
 )
 
 const (
@@ -93,6 +95,8 @@ func newDCState(state int, cs *cacheStore) dcState {
 		s = &unstableDC{}
 	case dcDown:
 		s = &downDC{}
+	case dcUnchanged:
+		s = &unchangedDC{}
 	}
 	s.init(cs)
 	s.tick()
@@ -115,6 +119,12 @@ func (dc *baseDC) checkCacheOp() error { return nil }
 func (dc *baseDC) beforeCacheOp()      {}
 func (dc *baseDC) afterCacheOp()       {}
 
+type unchangedDC struct {
+	baseDC
+}
+
+func (dc *unchangedDC) state() int { return dcUnchanged }
+
 type normalDC struct {
 	baseDC
 	ioErrCnt uint32