From b39592c02e8e87337a10ffc66051f17dc8d8b4ff Mon Sep 17 00:00:00 2001
From: ngaut <ngaut@126.com>
Date: Wed, 28 Oct 2015 13:48:45 +0800
Subject: [PATCH] kv: Do Lock key when create unique index

Fix #461
---
 kv/index_iter.go | 22 +++++++++++++---------
 session.go       |  2 +-
 tidb_test.go     | 15 +++++++++++++++
 3 files changed, 29 insertions(+), 10 deletions(-)

diff --git a/kv/index_iter.go b/kv/index_iter.go
index e19004ddeb941..d40c8e3af636e 100644
--- a/kv/index_iter.go
+++ b/kv/index_iter.go
@@ -159,20 +159,24 @@ func (c *kvIndex) genIndexKey(indexedValues []interface{}, h int64) ([]byte, err
 // Create creates a new entry in the kvIndex data.
 // If the index is unique and there already exists an entry with the same key, Create will return ErrKeyExists
 func (c *kvIndex) Create(txn Transaction, indexedValues []interface{}, h int64) error {
-	keyBuf, err := c.genIndexKey(indexedValues, h)
+	key, err := c.genIndexKey(indexedValues, h)
 	if err != nil {
 		return errors.Trace(err)
 	}
 	if !c.unique {
 		// TODO: reconsider value
-		err = txn.Set(keyBuf, []byte("timestamp?"))
+		err = txn.Set(key, []byte("timestamp?"))
 		return errors.Trace(err)
 	}
 
 	// unique index
-	_, err = txn.Get(keyBuf)
+	err = txn.LockKeys(key)
+	if err != nil {
+		return errors.Trace(err)
+	}
+	_, err = txn.Get(key)
 	if IsErrNotFound(err) {
-		err = txn.Set(keyBuf, encodeHandle(h))
+		err = txn.Set(key, encodeHandle(h))
 		return errors.Trace(err)
 	}
 
@@ -181,11 +185,11 @@ func (c *kvIndex) Create(txn Transaction, indexedValues []interface{}, h int64)
 
 // Delete removes the entry for handle h and indexdValues from KV index.
 func (c *kvIndex) Delete(txn Transaction, indexedValues []interface{}, h int64) error {
-	keyBuf, err := c.genIndexKey(indexedValues, h)
+	key, err := c.genIndexKey(indexedValues, h)
 	if err != nil {
 		return errors.Trace(err)
 	}
-	err = txn.Delete(keyBuf)
+	err = txn.Delete(key)
 	return errors.Trace(err)
 }
 
@@ -217,17 +221,17 @@ func (c *kvIndex) Drop(txn Transaction) error {
 
 // Seek searches KV index for the entry with indexedValues.
 func (c *kvIndex) Seek(txn Transaction, indexedValues []interface{}) (iter IndexIterator, hit bool, err error) {
-	keyBuf, err := c.genIndexKey(indexedValues, 0)
+	key, err := c.genIndexKey(indexedValues, 0)
 	if err != nil {
 		return nil, false, errors.Trace(err)
 	}
-	it, err := txn.Seek(keyBuf)
+	it, err := txn.Seek(key)
 	if err != nil {
 		return nil, false, errors.Trace(err)
 	}
 	// check if hit
 	hit = false
-	if it.Valid() && it.Key() == string(keyBuf) {
+	if it.Valid() && it.Key() == string(key) {
 		hit = true
 	}
 	return &indexIter{it: it, idx: c, prefix: c.prefix}, hit, nil
diff --git a/session.go b/session.go
index 8e4adf2cacb82..44a2a3c580a7e 100644
--- a/session.go
+++ b/session.go
@@ -256,7 +256,7 @@ func (s *session) ExecRestrictedSQL(ctx context.Context, sql string) (rset.Recor
 	// Check statement for some restriction
 	// For example only support DML on system meta table.
 	// TODO: Add more restrictions.
-	log.Infof("Executing %s [%s]", st, sql)
+	log.Infof("Executing %s [%s]", st.OriginText(), sql)
 	ctx.SetValue(&sqlexec.RestrictedSQLExecutorKeyType{}, true)
 	defer ctx.ClearValue(&sqlexec.RestrictedSQLExecutorKeyType{})
 	rs, err := st.Exec(ctx)
diff --git a/tidb_test.go b/tidb_test.go
index 3aaa755704610..fa6d38223b2b0 100644
--- a/tidb_test.go
+++ b/tidb_test.go
@@ -1245,6 +1245,21 @@ func (s *testSessionSuite) TestResultType(c *C) {
 	c.Assert(fs[0].Col.FieldType.Tp, Equals, mysql.TypeString)
 }
 
+func (s *testSessionSuite) TestIssue461(c *C) {
+	// Testcase for https://github.com/pingcap/tidb/issues/325
+	store := newStore(c, s.dbName)
+	se1 := newSession(c, store, s.dbName)
+	mustExecSQL(c, se1,
+		`CREATE TABLE test ( id int(11) UNSIGNED NOT NULL AUTO_INCREMENT, val int UNIQUE, PRIMARY KEY (id)); `)
+	mustExecSQL(c, se1, "begin;")
+	mustExecSQL(c, se1, "insert into test(id, val) values(1, 1);")
+	se2 := newSession(c, store, s.dbName)
+	mustExecSQL(c, se2, "begin;")
+	mustExecSQL(c, se2, "insert into test(id, val) values(1, 1);")
+	mustExecSQL(c, se2, "commit;")
+	mustExecFailed(c, se1, "commit;")
+}
+
 func (s *testSessionSuite) TestBuiltin(c *C) {
 	store := newStore(c, s.dbName)
 	se := newSession(c, store, s.dbName)