* fix timestamp default value bug in multiple time zones. (#9115) (#9108)

ddl/column.go

@@ -246,6 +246,12 @@ func onDropColumn(t *meta.Meta, job *model.Job) (ver int64, _ error) {
 		// NOTE: If the state of StateWriteOnly can be rollbacked, we'd better reconsider the original default value.
 		// And we need consider the column without not-null flag.
 		if colInfo.OriginDefaultValue == nil && mysql.HasNotNullFlag(colInfo.Flag) {
+			// If the column is timestamp default current_timestamp, and DDL owner is new version TiDB that set column.Version to 1,
+			// then old TiDB update record in the column write only stage will uses the wrong default value of the dropping column.
+			// Because new version of the column default value is UTC time, but old version TiDB will think the default value is the time in system timezone.
+			// But currently will be ok, because we can't cancel the drop column job when the job is running,
+			// so the column will be dropped succeed and client will never see the wrong default value of the dropped column.
+			// More info about this problem, see PR#9115.
 			colInfo.OriginDefaultValue, err = generateOriginDefaultValue(colInfo)
 			if err != nil {
 				return ver, errors.Trace(err)
@@ -463,9 +469,16 @@ func generateOriginDefaultValue(col *model.ColumnInfo) (interface{}, error) {
 		}
 	}
 
-	if odValue == strings.ToUpper(ast.CurrentTimestamp) &&
-		(col.Tp == mysql.TypeTimestamp || col.Tp == mysql.TypeDatetime) {
-		odValue = time.Now().Format(types.TimeFormat)
+	if odValue == strings.ToUpper(ast.CurrentTimestamp) {
+		if col.Tp == mysql.TypeTimestamp {
+			odValue = time.Now().UTC().Format(types.TimeFormat)
+			// Version = 1: For OriginDefaultValue and DefaultValue of timestamp column will stores the default time in UTC time zone.
+			//              This will fix bug in version 0.
+			// TODO: remove this version field after there is no old version 0.
+			col.Version = model.ColumnInfoVersion1
+		} else if col.Tp == mysql.TypeDatetime {
+			odValue = time.Now().Format(types.TimeFormat)
+		}
 	}
 	return odValue, nil
 }

ddl/ddl_api.go

@@ -21,6 +21,7 @@ import (
 	"bytes"
 	"fmt"
 	"strings"
+	"time"
 
 	"github.com/cznic/mathutil"
 	"github.com/pingcap/errors"
@@ -299,6 +300,30 @@ func checkColumnDefaultValue(ctx sessionctx.Context, col *table.Column, value in
 	return hasDefaultValue, value, nil
 }
 
+func convertTimestampDefaultValToUTC(ctx sessionctx.Context, defaultVal interface{}, col *table.Column) (interface{}, error) {
+	if defaultVal == nil || col.Tp != mysql.TypeTimestamp {
+		return defaultVal, nil
+	}
+	if vv, ok := defaultVal.(string); ok {
+		if vv != types.ZeroDatetimeStr && strings.ToUpper(vv) != strings.ToUpper(ast.CurrentTimestamp) {
+			t, err := types.ParseTime(ctx.GetSessionVars().StmtCtx, vv, col.Tp, col.Decimal)
+			if err != nil {
+				return defaultVal, errors.Trace(err)
+			}
+			err = t.ConvertTimeZone(ctx.GetSessionVars().Location(), time.UTC)
+			if err != nil {
+				return defaultVal, errors.Trace(err)
+			}
+			defaultVal = t.String()
+			// Version = 1: For OriginDefaultValue and DefaultValue of timestamp column will stores the default time in UTC time zone.
+			//              This will fix bug in version 0.
+			// TODO: remove this version field after there is no old version 0.
+			col.Version = model.ColumnInfoVersion1
+		}
+	}
+	return defaultVal, nil
+}
+
 // isExplicitTimeStamp is used to check if explicit_defaults_for_timestamp is on or off.
 // Check out this link for more details.
 // https://dev.mysql.com/doc/refman/5.7/en/server-system-variables.html#sysvar_explicit_defaults_for_timestamp
@@ -325,7 +350,7 @@ func columnDefToCol(ctx sessionctx.Context, offset int, colDef *ast.ColumnDef, o
 			col.Flag |= mysql.NotNullFlag
 		}
 	}
-
+	var err error
 	setOnUpdateNow := false
 	hasDefaultValue := false
 	hasNullFlag := false
@@ -358,14 +383,8 @@ func columnDefToCol(ctx sessionctx.Context, offset int, colDef *ast.ColumnDef, o
 				constraints = append(constraints, constraint)
 				col.Flag |= mysql.UniqueKeyFlag
 			case ast.ColumnOptionDefaultValue:
-				value, err := getDefaultValue(ctx, v, colDef.Tp.Tp, colDef.Tp.Decimal)
+				hasDefaultValue, err = setDefaultValue(ctx, col, v)
 				if err != nil {
-					return nil, nil, ErrColumnBadNull.GenWithStack("invalid default value - %s", err)
-				}
-				if hasDefaultValue, value, err = checkColumnDefaultValue(ctx, col, value); err != nil {
-					return nil, nil, errors.Trace(err)
-				}
-				if err = col.SetDefaultValue(value); err != nil {
 					return nil, nil, errors.Trace(err)
 				}
 				removeOnUpdateNowFlag(col)
@@ -422,7 +441,7 @@ func columnDefToCol(ctx sessionctx.Context, offset int, colDef *ast.ColumnDef, o
 	if mysql.HasZerofillFlag(col.Flag) {
 		col.Flag |= mysql.UnsignedFlag
 	}
-	err := checkPriKeyConstraint(col, hasDefaultValue, hasNullFlag, outPriKeyConstraint)
+	err = checkPriKeyConstraint(col, hasDefaultValue, hasNullFlag, outPriKeyConstraint)
 	if err != nil {
 		return nil, nil, errors.Trace(err)
 	}
@@ -433,7 +452,8 @@ func columnDefToCol(ctx sessionctx.Context, offset int, colDef *ast.ColumnDef, o
 	return col, constraints, nil
 }
 
-func getDefaultValue(ctx sessionctx.Context, c *ast.ColumnOption, tp byte, fsp int) (interface{}, error) {
+func getDefaultValue(ctx sessionctx.Context, c *ast.ColumnOption, t *types.FieldType) (interface{}, error) {
+	tp, fsp := t.Tp, t.Decimal
 	if tp == mysql.TypeTimestamp || tp == mysql.TypeDatetime {
 		vd, err := expression.GetTimeValue(ctx, c.Expr, tp, fsp)
 		value := vd.GetValue()
@@ -1673,16 +1693,25 @@ func modifiable(origin *types.FieldType, to *types.FieldType) error {
 	return errUnsupportedModifyColumn.GenWithStackByArgs(msg)
 }
 
-func setDefaultValue(ctx sessionctx.Context, col *table.Column, option *ast.ColumnOption) error {
-	value, err := getDefaultValue(ctx, option, col.Tp, col.Decimal)
+func setDefaultValue(ctx sessionctx.Context, col *table.Column, option *ast.ColumnOption) (bool, error) {
+	hasDefaultValue := false
+	value, err := getDefaultValue(ctx, option, &col.FieldType)
+	if err != nil {
+		return hasDefaultValue, ErrColumnBadNull.GenWithStack("invalid default value - %s", err)
+	}
+
+	if hasDefaultValue, value, err = checkColumnDefaultValue(ctx, col, value); err != nil {
+		return hasDefaultValue, errors.Trace(err)
+	}
+	value, err = convertTimestampDefaultValToUTC(ctx, value, col)
 	if err != nil {
-		return ErrColumnBadNull.GenWithStack("invalid default value - %s", err)
+		return hasDefaultValue, errors.Trace(err)
 	}
 	err = col.SetDefaultValue(value)
 	if err != nil {
-		return errors.Trace(err)
+		return hasDefaultValue, errors.Trace(err)
 	}
-	return errors.Trace(checkDefaultValue(ctx, col, true))
+	return hasDefaultValue, nil
 }
 
 func setColumnComment(ctx sessionctx.Context, col *table.Column, option *ast.ColumnOption) error {
@@ -1700,17 +1729,12 @@ func setDefaultAndComment(ctx sessionctx.Context, col *table.Column, options []*
 		return nil
 	}
 	var hasDefaultValue, setOnUpdateNow bool
+	var err error
 	for _, opt := range options {
 		switch opt.Tp {
 		case ast.ColumnOptionDefaultValue:
-			value, err := getDefaultValue(ctx, opt, col.Tp, col.Decimal)
+			hasDefaultValue, err = setDefaultValue(ctx, col, opt)
 			if err != nil {
-				return ErrColumnBadNull.GenWithStack("invalid default value - %s", err)
-			}
-			if hasDefaultValue, value, err = checkColumnDefaultValue(ctx, col, value); err != nil {
-				return errors.Trace(err)
-			}
-			if err = col.SetDefaultValue(value); err != nil {
 				return errors.Trace(err)
 			}
 		case ast.ColumnOptionComment:
@@ -1945,10 +1969,13 @@ func (d *ddl) AlterColumn(ctx sessionctx.Context, ident ast.Ident, spec *ast.Alt
 		}
 		setNoDefaultValueFlag(col, false)
 	} else {
-		err = setDefaultValue(ctx, col, specNewColumn.Options[0])
+		hasDefaultValue, err := setDefaultValue(ctx, col, specNewColumn.Options[0])
 		if err != nil {
 			return errors.Trace(err)
 		}
+		if err = checkDefaultValue(ctx, col, hasDefaultValue); err != nil {
+			return errors.Trace(err)
+		}
 	}
 
 	job := &model.Job{

executor/admin_test.go

@@ -507,6 +507,14 @@ func (s *testSuite) TestAdminCheckTable(c *C) {
 	tk.MustExec(`ALTER TABLE td1 ADD COLUMN c4 DECIMAL(12,8) NULL DEFAULT '213.41598062';`)
 	tk.MustExec(`ALTER TABLE td1 ADD INDEX id2 (c4) ;`)
 	tk.MustExec(`ADMIN CHECK TABLE td1;`)
+
+	// Test add not null column, then add index.
+	tk.MustExec(`drop table if exists t1`)
+	tk.MustExec(`create table t1 (a int);`)
+	tk.MustExec(`insert into t1 set a=2;`)
+	tk.MustExec(`alter table t1 add column b timestamp not null;`)
+	tk.MustExec(`alter table t1 add index(b);`)
+	tk.MustExec(`admin check table t1;`)
 }
 
 func (s *testSuite) TestAdminCheckPrimaryIndex(c *C) {

executor/executor_test.go

@@ -37,6 +37,7 @@ import (
 	"github.com/pingcap/tidb/config"
 	"github.com/pingcap/tidb/domain"
 	"github.com/pingcap/tidb/executor"
+	"github.com/pingcap/tidb/expression"
 	"github.com/pingcap/tidb/kv"
 	"github.com/pingcap/tidb/meta/autoid"
 	plannercore "github.com/pingcap/tidb/planner/core"
@@ -2130,6 +2131,74 @@ func (s *testSuite) TestTimestampTimeZone(c *C) {
 	r.Check(testkit.Rows("2014-03-31 08:57:10"))
 }
 
+func (s *testSuite) TestTimestampDefaultValueTimeZone(c *C) {
+	tk := testkit.NewTestKit(c, s.store)
+	tk.MustExec("use test")
+	tk.MustExec("drop table if exists t")
+	tk.MustExec("set time_zone = '+08:00'")
+	tk.MustExec(`create table t (a int, b timestamp default "2019-01-17 14:46:14")`)
+	tk.MustExec("insert into t set a=1")
+	r := tk.MustQuery(`show create table t`)
+	r.Check(testkit.Rows("t CREATE TABLE `t` (\n" + "  `a` int(11) DEFAULT NULL,\n" + "  `b` timestamp DEFAULT '2019-01-17 14:46:14'\n" + ") ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_bin"))
+	tk.MustExec("set time_zone = '+00:00'")
+	tk.MustExec("insert into t set a=2")
+	r = tk.MustQuery(`show create table t`)
+	r.Check(testkit.Rows("t CREATE TABLE `t` (\n" + "  `a` int(11) DEFAULT NULL,\n" + "  `b` timestamp DEFAULT '2019-01-17 06:46:14'\n" + ") ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_bin"))
+	r = tk.MustQuery(`select a,b from t order by a`)
+	r.Check(testkit.Rows("1 2019-01-17 06:46:14", "2 2019-01-17 06:46:14"))
+	tk.MustExec("set time_zone = '+08:00'")
+	r = tk.MustQuery(`select a,b from t order by a`)
+	r.Check(testkit.Rows("1 2019-01-17 14:46:14", "2 2019-01-17 14:46:14"))
+	tk.MustExec("set time_zone = '-08:00'")
+	r = tk.MustQuery(`show create table t`)
+	r.Check(testkit.Rows("t CREATE TABLE `t` (\n" + "  `a` int(11) DEFAULT NULL,\n" + "  `b` timestamp DEFAULT '2019-01-16 22:46:14'\n" + ") ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_bin"))
+
+	// test zero default value in multiple time zone.
+	defer tk.MustExec(fmt.Sprintf("set @@sql_mode='%s'", tk.MustQuery("select @@sql_mode").Rows()[0][0]))
+	tk.MustExec("set @@sql_mode='STRICT_TRANS_TABLES,NO_ENGINE_SUBSTITUTION';")
+	tk.MustExec("drop table if exists t")
+	tk.MustExec("set time_zone = '+08:00'")
+	tk.MustExec(`create table t (a int, b timestamp default "0000-00-00 00:00:00")`)
+	tk.MustExec("insert into t set a=1")
+	r = tk.MustQuery(`show create table t`)
+	r.Check(testkit.Rows("t CREATE TABLE `t` (\n" + "  `a` int(11) DEFAULT NULL,\n" + "  `b` timestamp DEFAULT '0000-00-00 00:00:00'\n" + ") ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_bin"))
+	tk.MustExec("set time_zone = '+00:00'")
+	tk.MustExec("insert into t set a=2")
+	r = tk.MustQuery(`show create table t`)
+	r.Check(testkit.Rows("t CREATE TABLE `t` (\n" + "  `a` int(11) DEFAULT NULL,\n" + "  `b` timestamp DEFAULT '0000-00-00 00:00:00'\n" + ") ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_bin"))
+	tk.MustExec("set time_zone = '-08:00'")
+	tk.MustExec("insert into t set a=3")
+	r = tk.MustQuery(`show create table t`)
+	r.Check(testkit.Rows("t CREATE TABLE `t` (\n" + "  `a` int(11) DEFAULT NULL,\n" + "  `b` timestamp DEFAULT '0000-00-00 00:00:00'\n" + ") ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_bin"))
+	r = tk.MustQuery(`select a,b from t order by a`)
+	r.Check(testkit.Rows("1 0000-00-00 00:00:00", "2 0000-00-00 00:00:00", "3 0000-00-00 00:00:00"))
+
+	// test add timestamp column default current_timestamp.
+	tk.MustExec(`drop table if exists t`)
+	tk.MustExec(`set time_zone = 'Asia/Shanghai'`)
+	tk.MustExec(`create table t (a int)`)
+	tk.MustExec(`insert into t set a=1`)
+	tk.MustExec(`alter table t add column b timestamp not null default current_timestamp;`)
+	timeIn8 := tk.MustQuery("select b from t").Rows()[0][0]
+	tk.MustExec(`set time_zone = '+00:00'`)
+	timeIn0 := tk.MustQuery("select b from t").Rows()[0][0]
+	c.Assert(timeIn8 != timeIn0, IsTrue, Commentf("%v == %v", timeIn8, timeIn0))
+	datumTimeIn8, err := expression.GetTimeValue(tk.Se, timeIn8, mysql.TypeTimestamp, 0)
+	c.Assert(err, IsNil)
+	tIn8To0 := datumTimeIn8.GetMysqlTime()
+	timeZoneIn8, err := time.LoadLocation("Asia/Shanghai")
+	c.Assert(err, IsNil)
+	err = tIn8To0.ConvertTimeZone(timeZoneIn8, time.UTC)
+	c.Assert(err, IsNil)
+	c.Assert(timeIn0 == tIn8To0.String(), IsTrue, Commentf("%v != %v", timeIn0, tIn8To0.String()))
+
+	// test add index.
+	tk.MustExec(`alter table t add index(b);`)
+	tk.MustExec("admin check table t")
+	tk.MustExec(`set time_zone = '+05:00'`)
+	tk.MustExec("admin check table t")
+}
+
 func (s *testSuite) TestTiDBCurrentTS(c *C) {
 	tk := testkit.NewTestKit(c, s.store)
 	tk.MustQuery("select @@tidb_current_ts").Check(testkit.Rows("0"))

executor/show.go

@@ -276,6 +276,25 @@ func (e *ShowExec) fetchShowColumns() error {
 		}
 
 		desc := table.NewColDesc(col)
+		var columnDefault interface{}
+		if desc.DefaultValue != nil {
+			// SHOW COLUMNS result expects string value
+			defaultValStr := fmt.Sprintf("%v", desc.DefaultValue)
+			// If column is timestamp, and default value is not current_timestamp, should convert the default value to the current session time zone.
+			if col.Tp == mysql.TypeTimestamp && defaultValStr != types.ZeroDatetimeStr && strings.ToUpper(defaultValStr) != strings.ToUpper(ast.CurrentTimestamp) {
+				timeValue, err := table.GetColDefaultValue(e.ctx, col.ToInfo())
+				if err != nil {
+					return errors.Trace(err)
+				}
+				defaultValStr = timeValue.GetMysqlTime().String()
+			}
+			if col.Tp == mysql.TypeBit {
+				defaultValBinaryLiteral := types.BinaryLiteral(defaultValStr)
+				columnDefault = defaultValBinaryLiteral.ToBitLiteralString(true)
+			} else {
+				columnDefault = defaultValStr
+			}
+		}
 
 		// The FULL keyword causes the output to include the column collation and comments,
 		// as well as the privileges you have for each column.
@@ -286,7 +305,7 @@ func (e *ShowExec) fetchShowColumns() error {
 				desc.Collation,
 				desc.Null,
 				desc.Key,
-				desc.DefaultValue,
+				columnDefault,
 				desc.Extra,
 				desc.Privileges,
 				desc.Comment,
@@ -297,7 +316,7 @@ func (e *ShowExec) fetchShowColumns() error {
 				desc.Type,
 				desc.Null,
 				desc.Key,
-				desc.DefaultValue,
+				columnDefault,
 				desc.Extra,
 			})
 		}
@@ -543,6 +562,15 @@ func (e *ShowExec) fetchShowCreateTable() error {
 					buf.WriteString(" DEFAULT CURRENT_TIMESTAMP")
 				default:
 					defaultValStr := fmt.Sprintf("%v", defaultValue)
+					// If column is timestamp, and default value is not current_timestamp, should convert the default value to the current session time zone.
+					if col.Tp == mysql.TypeTimestamp && defaultValStr != types.ZeroDatetimeStr {
+						timeValue, err := table.GetColDefaultValue(e.ctx, col.ToInfo())
+						if err != nil {
+							return errors.Trace(err)
+						}
+						defaultValStr = timeValue.GetMysqlTime().String()
+					}
+
 					if col.Tp == mysql.TypeBit {
 						defaultValBinaryLiteral := types.BinaryLiteral(defaultValStr)
 						buf.WriteString(fmt.Sprintf(" DEFAULT %s", defaultValBinaryLiteral.ToBitLiteralString(true)))

go.mod

@@ -81,3 +81,5 @@ require (
 	gopkg.in/tomb.v1 v1.0.0-20141024135613-dd632973f1e7 // indirect
 	gopkg.in/yaml.v2 v2.2.1 // indirect
 )
+
+replace github.com/pingcap/parser => github.com/crazycs520/parser v0.0.0-20190221063202-f830e9210447

go.sum

@@ -20,6 +20,8 @@ github.com/coreos/go-systemd v0.0.0-20180202092358-40e2722dffea h1:IHPWgevPcOUjT
 github.com/coreos/go-systemd v0.0.0-20180202092358-40e2722dffea/go.mod h1:F5haX7vjVVG0kc13fIWeqUViNPyEJxv/OmvnBo0Yme4=
 github.com/coreos/pkg v0.0.0-20160727233714-3ac0863d7acf h1:CAKfRE2YtTUIjjh1bkBtyYFaUT/WmOqsJjgtihT0vMI=
 github.com/coreos/pkg v0.0.0-20160727233714-3ac0863d7acf/go.mod h1:E3G3o1h8I7cfcXa63jLwjI0eiQQMgzzUDFVpN/nH/eA=
+github.com/crazycs520/parser v0.0.0-20190221063202-f830e9210447 h1:ZeTcpxSR4nUI9LP4HXyTiU//euTHaCewBEufdno24z0=
+github.com/crazycs520/parser v0.0.0-20190221063202-f830e9210447/go.mod h1:xLjI+gnWYexq011WPMEvCNS8rFM9qe1vdojIEzSKPuc=
 github.com/cznic/mathutil v0.0.0-20160613104831-78ad7f262603 h1:hhR9hTi0ligs11JjfGDBP332clNOJRdW0Ci5oHtEC+0=
 github.com/cznic/mathutil v0.0.0-20160613104831-78ad7f262603/go.mod h1:e6NPNENfs9mPDVNRekM7lKScauxd5kXTr1Mfyig6TDM=
 github.com/cznic/sortutil v0.0.0-20150617083342-4c7342852e65 h1:hxuZop6tSoOi0sxFzoGGYdRqNrPubyaIf9KoBG9tPiE=