github.com/insionng/yougam@v0.0.0-20170714101924-2bc18d833463/libraries/pingcap/tidb/store/tikv/txn.go (about)

     1  // Copyright 2016 PingCAP, Inc.
     2  //
     3  // Licensed under the Apache License, Version 2.0 (the "License");
     4  // you may not use this file except in compliance with the License.
     5  // You may obtain a copy of the License at
     6  //
     7  //     http://www.apache.org/licenses/LICENSE-2.0
     8  //
     9  // Unless required by applicable law or agreed to in writing, software
    10  // distributed under the License is distributed on an "AS IS" BASIS,
    11  // See the License for the specific language governing permissions and
    12  // limitations under the License.
    13  
    14  package tikv
    15  
    16  import (
    17  	"fmt"
    18  
    19  	"github.com/insionng/yougam/libraries/juju/errors"
    20  	"github.com/insionng/yougam/libraries/ngaut/log"
    21  	"github.com/insionng/yougam/libraries/pingcap/tidb/kv"
    22  )
    23  
    24  var (
    25  	_ kv.Transaction = (*tikvTxn)(nil)
    26  )
    27  
    28  // tikvTxn implements kv.Transaction.
    29  type tikvTxn struct {
    30  	us       kv.UnionStore
    31  	store    *tikvStore // for connection to region.
    32  	startTS  uint64
    33  	commitTS uint64
    34  	valid    bool
    35  	lockKeys [][]byte
    36  	dirty    bool
    37  	// FIXME: only doPrewrite, this variable only for lock key test.
    38  	// If find better way to test lock then delete it.
    39  	DONOTCOMMIT bool
    40  }
    41  
    42  func newTiKVTxn(store *tikvStore) (*tikvTxn, error) {
    43  	startTS, err := store.oracle.GetTimestamp()
    44  	if err != nil {
    45  		return nil, errors.Trace(err)
    46  	}
    47  	ver := kv.NewVersion(startTS)
    48  	return &tikvTxn{
    49  		us:      kv.NewUnionStore(newTiKVSnapshot(store, ver)),
    50  		store:   store,
    51  		startTS: startTS,
    52  		valid:   true,
    53  	}, nil
    54  }
    55  
    56  // Implement transaction interface.
    57  func (txn *tikvTxn) Get(k kv.Key) ([]byte, error) {
    58  	log.Debugf("Get key[%q] txn[%d]", k, txn.StartTS())
    59  	ret, err := txn.us.Get(k)
    60  	if err != nil {
    61  		return nil, errors.Trace(err)
    62  	}
    63  	return ret, nil
    64  }
    65  
    66  func (txn *tikvTxn) Set(k kv.Key, v []byte) error {
    67  	log.Debugf("Set key[%q] txn[%d]", k, txn.StartTS())
    68  	txn.dirty = true
    69  	return txn.us.Set(k, v)
    70  }
    71  
    72  func (txn *tikvTxn) String() string {
    73  	return fmt.Sprintf("%d", txn.StartTS())
    74  }
    75  
    76  func (txn *tikvTxn) Seek(k kv.Key) (kv.Iterator, error) {
    77  	log.Debugf("Seek key[%q] txn[%d]", k, txn.StartTS())
    78  	return txn.us.Seek(k)
    79  }
    80  
    81  // SeekReverse creates a reversed Iterator positioned on the first entry which key is less than k.
    82  func (txn *tikvTxn) SeekReverse(k kv.Key) (kv.Iterator, error) {
    83  	log.Debugf("SeekReverse key[%q] txn[%d]", k, txn.StartTS())
    84  	return txn.us.SeekReverse(k)
    85  }
    86  
    87  func (txn *tikvTxn) Delete(k kv.Key) error {
    88  	log.Debugf("Delete key[%q] txn[%d]", k, txn.StartTS())
    89  	txn.dirty = true
    90  	return txn.us.Delete(k)
    91  }
    92  
    93  func (txn *tikvTxn) SetOption(opt kv.Option, val interface{}) {
    94  	txn.us.SetOption(opt, val)
    95  }
    96  
    97  func (txn *tikvTxn) DelOption(opt kv.Option) {
    98  	txn.us.DelOption(opt)
    99  }
   100  
   101  func (txn *tikvTxn) Commit() error {
   102  	if !txn.valid {
   103  		return kv.ErrInvalidTxn
   104  	}
   105  	defer txn.close()
   106  
   107  	log.Debugf("[kv] start to commit txn %d", txn.StartTS())
   108  	if err := txn.us.CheckLazyConditionPairs(); err != nil {
   109  		return errors.Trace(err)
   110  	}
   111  
   112  	committer, err := newTxnCommitter(txn)
   113  	if err != nil {
   114  		return errors.Trace(err)
   115  	}
   116  	if committer == nil {
   117  		return nil
   118  	}
   119  	err = committer.Commit()
   120  	if err != nil {
   121  		return errors.Trace(err)
   122  	}
   123  	log.Debugf("[kv] finish commit txn %d", txn.StartTS())
   124  	return nil
   125  }
   126  
   127  func (txn *tikvTxn) close() error {
   128  	txn.us.Release()
   129  	txn.valid = false
   130  	return nil
   131  }
   132  
   133  func (txn *tikvTxn) Rollback() error {
   134  	if !txn.valid {
   135  		return kv.ErrInvalidTxn
   136  	}
   137  	log.Warnf("[kv] Rollback txn %d", txn.StartTS())
   138  	return nil
   139  }
   140  
   141  func (txn *tikvTxn) LockKeys(keys ...kv.Key) error {
   142  	for _, key := range keys {
   143  		txn.lockKeys = append(txn.lockKeys, key)
   144  	}
   145  	return nil
   146  }
   147  
   148  func (txn *tikvTxn) GetClient() kv.Client {
   149  	return &CopClient{
   150  		store: txn.store,
   151  	}
   152  }
   153  
   154  func (txn *tikvTxn) IsReadOnly() bool {
   155  	return !txn.dirty
   156  }
   157  
   158  func (txn *tikvTxn) StartTS() uint64 {
   159  	return txn.startTS
   160  }