store/tikv: fix performance issue under mixed transaction mode (#10847)

pingcap · Jun 20, 2019 · c0dc198 · c0dc198
1 parent 75b9470
commit c0dc198
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Showing 6 changed files with 45 additions and 12 deletions.
diff --git a/config/config.go b/config/config.go
@@ -35,7 +35,9 @@ import (
 
 // Config number limitations
 const (
- MaxLogFileSize = 4096 // MB
+ MaxLogFileSize = 4096 // MB
+ MinPessimisticTTL = time.Second * 15
+ MaxPessimisticTTL = time.Second * 60
 )
 
 // Valid config maps
@@ -568,10 +570,9 @@ func (c *Config) Valid() error {
  if err != nil {
  return err
  }
- minDur := time.Second * 15
- maxDur := time.Second * 60
- if dur < minDur || dur > maxDur {
- return fmt.Errorf("pessimistic transaction ttl %s out of range [%s, %s]", dur, minDur, maxDur)
+ if dur < MinPessimisticTTL || dur > MaxPessimisticTTL {
+ return fmt.Errorf("pessimistic transaction ttl %s out of range [%s, %s]",
+ dur, MinPessimisticTTL, MaxPessimisticTTL)
  }
  }
  return nil

diff --git a/session/pessimistic_test.go b/session/pessimistic_test.go
@@ -27,6 +27,7 @@ import (
  "github.com/pingcap/tidb/session"
  "github.com/pingcap/tidb/store/mockstore"
  "github.com/pingcap/tidb/store/mockstore/mocktikv"
+ "github.com/pingcap/tidb/store/tikv"
  "github.com/pingcap/tidb/tablecodec"
  "github.com/pingcap/tidb/util/codec"
  "github.com/pingcap/tidb/util/testkit"
@@ -52,6 +53,7 @@ func (s *testPessimisticSuite) SetUpSuite(c *C) {
  mockstore.WithCluster(s.cluster),
  mockstore.WithMVCCStore(s.mvccStore),
  )
+ tikv.PessimisticLockTTL = uint64(config.MinPessimisticTTL / time.Millisecond)
  c.Assert(err, IsNil)
  s.store = store
  session.SetSchemaLease(0)

diff --git a/store/tikv/2pc.go b/store/tikv/2pc.go
@@ -538,6 +538,19 @@ func (c *twoPhaseCommitter) prewriteSingleBatch(bo *Backoffer, batch batchKeys)
  if err1 != nil {
  return errors.Trace(err1)
  }
+ if !c.isPessimistic && c.lockTTL < lock.TTL && lock.TTL >= uint64(config.MinPessimisticTTL/time.Millisecond) {
+ // An optimistic prewrite meets a pessimistic or large transaction lock.
+ // If we wait for the lock, other written optimistic locks would block reads for long time.
+ // And it is very unlikely this transaction would succeed after wait for the long TTL lock.
+ // Return write conflict error to cleanup locks.
+ return newWriteConflictError(&pb.WriteConflict{
+ StartTs: c.startTS,
+ ConflictTs: lock.TxnID,
+ ConflictCommitTs: 0,
+ Key: lock.Key,
+ Primary: lock.Primary,
+ })
+ }
  logutil.Logger(context.Background()).Debug("prewrite encounters lock",
  zap.Uint64("conn", c.connID),
  zap.Stringer("lock", lock))

diff --git a/store/tikv/2pc_test.go b/store/tikv/2pc_test.go
@@ -23,6 +23,7 @@ import (
  . "github.com/pingcap/check"
  "github.com/pingcap/errors"
  "github.com/pingcap/kvproto/pkg/kvrpcpb"
+ "github.com/pingcap/tidb/config"
  "github.com/pingcap/tidb/kv"
  "github.com/pingcap/tidb/store/mockstore/mocktikv"
  "github.com/pingcap/tidb/store/tikv/tikvrpc"
@@ -38,6 +39,7 @@ var _ = Suite(&testCommitterSuite{})
 
 func (s *testCommitterSuite) SetUpTest(c *C) {
  s.cluster = mocktikv.NewCluster()
+ PessimisticLockTTL = uint64(config.MinPessimisticTTL / time.Millisecond)
  mocktikv.BootstrapWithMultiRegions(s.cluster, []byte("a"), []byte("b"), []byte("c"))
  mvccStore, err := mocktikv.NewMVCCLevelDB("")
  c.Assert(err, IsNil)
@@ -468,3 +470,18 @@ func (s *testCommitterSuite) TestPessimisticLockedKeysDedup(c *C) {
  c.Assert(err, IsNil)
  c.Assert(txn.lockKeys, HasLen, 2)
 }
+
+func (s *testCommitterSuite) TestPessimistOptimisticConflict(c *C) {
+ txnPes := s.begin(c)
+ txnPes.SetOption(kv.Pessimistic, true)
+ err := txnPes.LockKeys(context.Background(), txnPes.startTS, kv.Key("pes"))
+ c.Assert(err, IsNil)
+ c.Assert(txnPes.IsPessimistic(), IsTrue)
+ c.Assert(txnPes.lockKeys, HasLen, 1)
+ txnOpt := s.begin(c)
+ err = txnOpt.Set(kv.Key("pes"), []byte("v"))
+ c.Assert(err, IsNil)
+ err = txnOpt.Commit(context.Background())
+ c.Assert(kv.ErrWriteConflict.Equal(err), IsTrue)
+ c.Assert(txnPes.Commit(context.Background()), IsNil)
+}
diff --git a/store/tikv/lock_resolver.go b/store/tikv/lock_resolver.go
@@ -138,17 +138,12 @@ func (l *Lock) String() string {
 
 // NewLock creates a new *Lock.
 func NewLock(l *kvrpcpb.LockInfo) *Lock {
- ttl := l.GetLockTtl()
- if ttl == 0 {
- ttl = defaultLockTTL
- }
- txnSize := l.GetTxnSize()
  return &Lock{
  Key: l.GetKey(),
  Primary: l.GetPrimaryLock(),
  TxnID: l.GetLockVersion(),
- TTL: ttl,
- TxnSize: txnSize,
+ TTL: l.GetLockTtl(),
+ TxnSize: l.GetTxnSize(),
  }
 }
 

diff --git a/store/tikv/lock_test.go b/store/tikv/lock_test.go
@@ -277,6 +277,11 @@ func (s *testLockSuite) TestLockTTL(c *C) {
  s.ttlEquals(c, l.TTL, defaultLockTTL+uint64(time.Since(start)/time.Millisecond))
 }
 
+func (s *testLockSuite) TestNewLockZeroTTL(c *C) {
+ l := NewLock(&kvrpcpb.LockInfo{})
+ c.Assert(l.TTL, Equals, uint64(0))
+}
+
 func init() {
  // Speed up tests.
  defaultLockTTL = 3