use global variable instead of config (#458)

Signed-off-by: Jack Yu <jackysp@gmail.com>

config/client.go

@@ -44,8 +44,6 @@ import (
 const (
 	// DefStoreLivenessTimeout is the default value for store liveness timeout.
 	DefStoreLivenessTimeout = "1s"
-	// DefTxnCommitBatchSize recommends each RPC packet should be less than ~1MB
-	DefTxnCommitBatchSize = 16 * 1024
 )
 
 // TiKVClient is the config for tikv client.
@@ -86,7 +84,6 @@ type TiKVClient struct {
 	// TTLRefreshedTxnSize controls whether a transaction should update its TTL or not.
 	TTLRefreshedTxnSize      int64  `toml:"ttl-refreshed-txn-size" json:"ttl-refreshed-txn-size"`
 	ResolveLockLiteThreshold uint64 `toml:"resolve-lock-lite-threshold" json:"resolve-lock-lite-threshold"`
-	TxnCommitBatchSize       uint   `toml:"txn-commit-batch-size" json:"txn-commit-batch-size"`
 }
 
 // AsyncCommit is the config for the async commit feature. The switch to enable it is a system variable.
@@ -155,7 +152,6 @@ func DefaultTiKVClient() TiKVClient {
 		},
 
 		ResolveLockLiteThreshold: 16,
-		TxnCommitBatchSize:       DefTxnCommitBatchSize,
 	}
 }
 

kv/store_vars.go

@@ -41,6 +41,17 @@ import (
 // StoreLimit will update from config reload and global variable set.
 var StoreLimit atomic.Int64
 
+// DefTxnCommitBatchSize is the default value of TxnCommitBatchSize.
+const DefTxnCommitBatchSize uint64 = 16 * 1024
+
+// TxnCommitBatchSize controls the batch size of transaction commit related requests sent by client to TiKV,
+// TiKV recommends each RPC packet should be less than ~1MB.
+var TxnCommitBatchSize atomic.Uint64
+
+func init() {
+	TxnCommitBatchSize.Store(DefTxnCommitBatchSize)
+}
+
 // ReplicaReadType is the type of replica to read data from
 type ReplicaReadType byte
 

txnkv/transaction/2pc.go

@@ -700,7 +700,7 @@ func txnLockTTL(startTime time.Time, txnSize int) uint64 {
 	// When writeSize is less than 256KB, the base ttl is defaultTTL (3s);
 	// When writeSize is 1MiB, 4MiB, or 10MiB, ttl is 6s, 12s, 20s correspondingly;
 	lockTTL := defaultLockTTL
-	if txnSize >= int(config.GetGlobalConfig().TiKVClient.TxnCommitBatchSize) {
+	if txnSize >= int(kv.TxnCommitBatchSize.Load()) {
 		sizeMiB := float64(txnSize) / bytesPerMiB
 		lockTTL = uint64(float64(ttlFactor) * math.Sqrt(sizeMiB))
 		if lockTTL < defaultLockTTL {
@@ -875,7 +875,7 @@ func (c *twoPhaseCommitter) doActionOnGroupMutations(bo *retry.Backoffer, action
 	batchBuilder := newBatched(c.primary())
 	for _, group := range groups {
 		batchBuilder.appendBatchMutationsBySize(group.region, group.mutations, sizeFunc,
-			int(config.GetGlobalConfig().TiKVClient.TxnCommitBatchSize))
+			int(kv.TxnCommitBatchSize.Load()))
 	}
 	firstIsPrimary := batchBuilder.setPrimary()
 

txnkv/transaction/test_probe.go

@@ -20,10 +20,10 @@ import (
 	"sync/atomic"
 	"time"
 
-	"github.com/tikv/client-go/v2/config"
 	"github.com/tikv/client-go/v2/internal/locate"
 	"github.com/tikv/client-go/v2/internal/retry"
 	"github.com/tikv/client-go/v2/internal/unionstore"
+	"github.com/tikv/client-go/v2/kv"
 	"github.com/tikv/client-go/v2/tikvrpc"
 	"github.com/tikv/client-go/v2/txnkv/txnsnapshot"
 )
@@ -330,7 +330,7 @@ type ConfigProbe struct{}
 
 // GetTxnCommitBatchSize returns the batch size to commit txn.
 func (c ConfigProbe) GetTxnCommitBatchSize() uint64 {
-	return uint64(config.GetGlobalConfig().TiKVClient.TxnCommitBatchSize)
+	return kv.TxnCommitBatchSize.Load()
 }
 
 // GetPessimisticLockMaxBackoff returns pessimisticLockMaxBackoff