store/tikv: make cache ttl configurable(#12647)

config/config.go

@@ -276,6 +276,9 @@ type TiKVClient struct {
 	MaxBatchWaitTime time.Duration `toml:"max-batch-wait-time" json:"max-batch-wait-time"`
 	// BatchWaitSize is the max wait size for batch.
 	BatchWaitSize uint `toml:"batch-wait-size" json:"batch-wait-size"`
+	// If a Region has not been accessed for more than the given duration (in seconds), it
+	// will be reloaded from the PD.
+	RegionCacheTTL uint `toml:"region-cache-ttl" json:"region-cache-ttl"`
 }
 
 // Binlog is the config for binlog.
@@ -395,6 +398,8 @@ var defaultConf = Config{
 		OverloadThreshold: 200,
 		MaxBatchWaitTime:  0,
 		BatchWaitSize:     8,
+
+		RegionCacheTTL: 600,
 	},
 	Binlog: Binlog{
 		WriteTimeout: "15s",

config/config.toml.example

@@ -267,6 +267,10 @@ max-batch-wait-time = 0
 # Batch wait size, to avoid waiting too long.
 batch-wait-size = 8
 
+# If a Region has not been accessed for more than the given duration (in seconds), it
+# will be reloaded from the PD.
+region-cache-ttl = 600
+
 [txn-local-latches]
 # Enable local latches for transactions. Enable it when
 # there are lots of conflicts between transactions.

config/config_test.go

@@ -39,6 +39,7 @@ func (s *testConfigSuite) TestConfig(c *C) {
 	conf.Binlog.IgnoreError = true
 	conf.Binlog.Strategy = "hash"
 	conf.TiKVClient.CommitTimeout = "10s"
+	conf.TiKVClient.RegionCacheTTL = 600
 	configFile := "config.toml"
 	_, localFile, _, _ := runtime.Caller(0)
 	configFile = path.Join(path.Dir(localFile), configFile)
@@ -65,6 +66,7 @@ split-region-max-num=10000
 [tikv-client]
 commit-timeout="41s"
 max-batch-size=128
+region-cache-ttl=6000
 [stmt-summary]
 max-stmt-count=1000
 max-sql-length=1024
@@ -81,6 +83,7 @@ max-sql-length=1024
 
 	c.Assert(conf.TiKVClient.CommitTimeout, Equals, "41s")
 	c.Assert(conf.TiKVClient.MaxBatchSize, Equals, uint(128))
+	c.Assert(conf.TiKVClient.RegionCacheTTL, Equals, uint(6000))
 	c.Assert(conf.TokenLimit, Equals, uint(1000))
 	c.Assert(conf.SplitRegionMaxNum, Equals, uint64(10000))
 	c.Assert(conf.StmtSummary.MaxStmtCount, Equals, uint(1000))

store/tikv/region_cache.go

@@ -33,11 +33,13 @@ import (
 )
 
 const (
-	btreeDegree                = 32
-	rcDefaultRegionCacheTTLSec = 600
-	invalidatedLastAccessTime  = -1
+	btreeDegree               = 32
+	invalidatedLastAccessTime = -1
 )
 
+// RegionCacheTTLSec is the max idle time for regions in the region cache.
+var RegionCacheTTLSec int64 = 600
+
 var (
 	tikvRegionCacheCounterWithInvalidateRegionFromCacheOK = metrics.TiKVRegionCacheCounter.WithLabelValues("invalidate_region_from_cache", "ok")
 	tikvRegionCacheCounterWithSendFail                    = metrics.TiKVRegionCacheCounter.WithLabelValues("send_fail", "ok")
@@ -121,7 +123,7 @@ func (r *Region) compareAndSwapStore(oldStore, newStore *RegionStore) bool {
 func (r *Region) checkRegionCacheTTL(ts int64) bool {
 	for {
 		lastAccess := atomic.LoadInt64(&r.lastAccess)
-		if ts-lastAccess > rcDefaultRegionCacheTTLSec {
+		if ts-lastAccess > RegionCacheTTLSec {
 			return false
 		}
 		if atomic.CompareAndSwapInt64(&r.lastAccess, lastAccess, ts) {

tidb-server/main.go

@@ -498,6 +498,7 @@ func setGlobalVars() {
 
 	tikv.CommitMaxBackoff = int(parseDuration(cfg.TiKVClient.CommitTimeout).Seconds() * 1000)
 	tikv.PessimisticLockTTL = uint64(parseDuration(cfg.PessimisticTxn.TTL).Seconds() * 1000)
+	tikv.RegionCacheTTLSec = int64(cfg.TiKVClient.RegionCacheTTL)
 }
 
 func setupLog() {