expression: add builtin function tidb_parse_tso (#8385)

expression/builtin.go

@@ -413,6 +413,7 @@ var funcs = map[string]functionClass{
 	ast.Year:             &yearFunctionClass{baseFunctionClass{ast.Year, 1, 1}},
 	ast.YearWeek:         &yearWeekFunctionClass{baseFunctionClass{ast.YearWeek, 1, 2}},
 	ast.LastDay:          &lastDayFunctionClass{baseFunctionClass{ast.LastDay, 1, 1}},
+	ast.TiDBParseTso:     &tidbParseTsoFunctionClass{baseFunctionClass{ast.TiDBParseTso, 1, 1}},
 
 	// string functions
 	ast.ASCII:           &asciiFunctionClass{baseFunctionClass{ast.ASCII, 1, 1}},

expression/builtin_time.go

@@ -31,6 +31,7 @@ import (
 	"github.com/pingcap/parser/terror"
 	"github.com/pingcap/tidb/sessionctx"
 	"github.com/pingcap/tidb/sessionctx/stmtctx"
+	"github.com/pingcap/tidb/store/tikv/oracle"
 	"github.com/pingcap/tidb/types"
 	"github.com/pingcap/tidb/util/chunk"
 	"github.com/pingcap/tipb/go-tipb"
@@ -5652,3 +5653,50 @@ func getExpressionFsp(ctx sessionctx.Context, expression Expression) (int, error
 	}
 	return mathutil.Min(expression.GetType().Decimal, types.MaxFsp), nil
 }
+
+//tidbParseTsoFunction extracts physical time from a tso
+type tidbParseTsoFunctionClass struct {
+	baseFunctionClass
+}
+
+func (c *tidbParseTsoFunctionClass) getFunction(ctx sessionctx.Context, args []Expression) (builtinFunc, error) {
+	if err := c.verifyArgs(args); err != nil {
+		return nil, errors.Trace(err)
+	}
+	argTp := args[0].GetType().EvalType()
+	bf := newBaseBuiltinFuncWithTp(ctx, args, argTp, types.ETInt)
+
+	bf.tp.Tp, bf.tp.Flen, bf.tp.Decimal = mysql.TypeDate, mysql.MaxDateWidth, types.DefaultFsp
+	sig := &builtinTidbParseTsoSig{bf}
+	return sig, nil
+}
+
+type builtinTidbParseTsoSig struct {
+	baseBuiltinFunc
+}
+
+func (b *builtinTidbParseTsoSig) Clone() builtinFunc {
+	newSig := &builtinTidbParseTsoSig{}
+	newSig.cloneFrom(&b.baseBuiltinFunc)
+	return newSig
+}
+
+// evalTime evals a builtinTidbParseTsoSig.
+func (b *builtinTidbParseTsoSig) evalTime(row chunk.Row) (types.Time, bool, error) {
+	arg, isNull, err := b.args[0].EvalInt(b.ctx, row)
+	if isNull || err != nil || arg <= 0 {
+		return types.Time{}, true, errors.Trace(handleInvalidTimeError(b.ctx, err))
+	}
+
+	t := oracle.GetTimeFromTS(uint64(arg))
+	result := types.Time{
+		Time: types.FromGoTime(t),
+		Type: mysql.TypeDatetime,
+		Fsp:  types.MaxFsp,
+	}
+	err = result.ConvertTimeZone(time.Local, b.ctx.GetSessionVars().Location())
+	if err != nil {
+		return types.Time{}, true, errors.Trace(err)
+	}
+	return result, false, nil
+}

expression/builtin_time_test.go

@@ -2389,3 +2389,40 @@ func (s *testEvaluatorSuite) TestWithTimeZone(c *C) {
 		c.Assert(result.Sub(now), LessEqual, 2*time.Second)
 	}
 }
+
+func (s *testEvaluatorSuite) TestTidbParseTso(c *C) {
+	s.ctx.GetSessionVars().TimeZone = time.UTC
+	tests := []struct {
+		param  interface{}
+		expect string
+	}{
+		{404411537129996288, "2018-11-20 09:53:04.877000"},
+		{"404411537129996288", "2018-11-20 09:53:04.877000"},
+		{1, "1970-01-01 00:00:00.000000"},
+	}
+
+	fc := funcs[ast.TiDBParseTso]
+	for _, test := range tests {
+		t := []types.Datum{types.NewDatum(test.param)}
+		f, err := fc.getFunction(s.ctx, s.datumsToConstants(t))
+		c.Assert(err, IsNil)
+		d, err := evalBuiltinFunc(f, chunk.Row{})
+		c.Assert(err, IsNil)
+		result, _ := d.ToString()
+		c.Assert(result, Equals, test.expect)
+	}
+
+	testsNull := []interface{}{
+		0,
+		-1,
+		"-1"}
+
+	for _, i := range testsNull {
+		t := []types.Datum{types.NewDatum(i)}
+		f, err := fc.getFunction(s.ctx, s.datumsToConstants(t))
+		c.Assert(err, IsNil)
+		d, err := evalBuiltinFunc(f, chunk.Row{})
+		c.Assert(err, IsNil)
+		c.Assert(d.IsNull(), IsTrue)
+	}
+}

expression/integration_test.go

@@ -1831,6 +1831,19 @@ func (s *testIntegrationSuite) TestTimeBuiltin(c *C) {
 	// for current_timestamp, current_timestamp()
 	result = tk.MustQuery(`select current_timestamp() = now(), current_timestamp = now()`)
 	result.Check(testkit.Rows("1 1"))
+
+	// for tidb_parse_tso
+	tk.MustExec("SET time_zone = '+00:00';")
+	result = tk.MustQuery(`select tidb_parse_tso(404411537129996288)`)
+	result.Check(testkit.Rows("2018-11-20 09:53:04.877000"))
+	result = tk.MustQuery(`select tidb_parse_tso("404411537129996288")`)
+	result.Check(testkit.Rows("2018-11-20 09:53:04.877000"))
+	result = tk.MustQuery(`select tidb_parse_tso(1)`)
+	result.Check(testkit.Rows("1970-01-01 00:00:00.000000"))
+	result = tk.MustQuery(`select tidb_parse_tso(0)`)
+	result.Check(testkit.Rows("<nil>"))
+	result = tk.MustQuery(`select tidb_parse_tso(-1)`)
+	result.Check(testkit.Rows("<nil>"))
 }
 
 func (s *testIntegrationSuite) TestOpBuiltin(c *C) {

go.mod

@@ -28,7 +28,7 @@ require (
 	github.com/pingcap/errors v0.11.0
 	github.com/pingcap/goleveldb v0.0.0-20171020122428-b9ff6c35079e
 	github.com/pingcap/kvproto v0.0.0-20181105061835-1b5d69cd1d26
-	github.com/pingcap/parser v0.0.0-20181120072820-10951bcfca73
+	github.com/pingcap/parser v0.0.0-20181126111651-a38036a60de7
 	github.com/pingcap/pd v2.1.0-rc.4+incompatible
 	github.com/pingcap/tidb-tools v0.0.0-20181112132202-4860a0d5de03
 	github.com/pingcap/tipb v0.0.0-20181012112600-11e33c750323

go.sum

@@ -209,6 +209,8 @@ github.com/pingcap/parser v0.0.0-20181113072426-4a9a1b13b591 h1:7lErVcNwgmWNgsZw
 github.com/pingcap/parser v0.0.0-20181113072426-4a9a1b13b591/go.mod h1:1FNvfp9+J0wvc4kl8eGNh7Rqrxveg15jJoWo/a0uHwA=
 github.com/pingcap/parser v0.0.0-20181120072820-10951bcfca73 h1:toHh8VsVgJTP9A4O/BO73T3i8RpvRTwuS9eMe7pZUK0=
 github.com/pingcap/parser v0.0.0-20181120072820-10951bcfca73/go.mod h1:1FNvfp9+J0wvc4kl8eGNh7Rqrxveg15jJoWo/a0uHwA=
+github.com/pingcap/parser v0.0.0-20181126111651-a38036a60de7 h1:E/T5kIrtzipWJhN/YREI+f3PiP6Uw5boE4KRcD+zVvo=
+github.com/pingcap/parser v0.0.0-20181126111651-a38036a60de7/go.mod h1:1FNvfp9+J0wvc4kl8eGNh7Rqrxveg15jJoWo/a0uHwA=
 github.com/pingcap/pd v0.0.0-20180619050643-0ec6ffcf94e8/go.mod h1:nD3+EoYes4+aNNODO99ES59V83MZSI+dFbhyr667a0E=
 github.com/pingcap/pd v0.0.0-20181015053559-eb892dda1e33 h1:UQKEV9u9PR1RjFiJqqGijsHAEzTDZe89xdgB4Lj9S8Y=
 github.com/pingcap/pd v0.0.0-20181015053559-eb892dda1e33/go.mod h1:+bFEXnol47I8RhLpb0RbP5ZvpG6Ca7dw0LL/ARsmRk0=