refine data truncate error msg

[crazycs520]

What problem does this PR solve?

fix #7390
In TiDB now:

mysql root@127.0.0.1:test> create table t(a bigint);
Query OK, 0 rows affected
Time: 0.008s
mysql root@127.0.0.1:test> insert into t values("asfasdfsajhlkhlksdaf");
(1366, "Incorrect bigint value: 'asfasdfsajhlkhlksdaf' for column 'a' at row 1")
mysql root@127.0.0.1:test> insert into t values("12asdf");
(1366, "Incorrect bigint value: '12asdf' for column 'a' at row 1")

In Mysql

mysql root@127.0.0.1:test> create table t (a bigint)
Query OK, 0 rows affected
Time: 0.018s
mysql root@127.0.0.1:test> insert into t values("asfasdfsajhlkhlksdaf");
(1366, "Incorrect integer value: 'asfasdfsajhlkhlksdaf' for column 'a' at row 1")
mysql root@127.0.0.1:test> insert into t values("12asdf");
(1265, "Data truncated for column 'a' at row 1")

As you can see, The return error of insert into t values("12asdf"); in TiDB is still different from MySQL.

What is changed and how it works?

Check List

Tests

[winkyao]

@crazycs520 Please read the https://github.com/pingcap/tidb/blob/master/CONTRIBUTING.md, and the proper commit message is :

<subsystem>: <what changed>
<BLANK LINE>
<why this change was made>
<BLANK LINE>
<footer>(optional)

Please follow this style.

[winkyao]

reset LGTM

[winkyao]

Add code map in line 213, in tableMySQLErrCodes.

[crazycs520]

codeTruncateWrongValue already in code map.

[winkyao]

Please make sure the error code is 1366

[crazycs520]

The error code of table.ErrTruncatedWrongValueForField is 1366.

[winkyao]

LGTM

[shenli]

Could you move the ToString() operation into the handErr() function? We could use a lazy way to call the ToString function. Or you will call ToString for all the data.

[crazycs520]

done.

[crazycs520]

@shenli here is a benchmark about datum and *datum:

func foo1 (d Datum){
        _ = d.Kind()
}

func foo2 (d *Datum){
        _ = d.Kind()
}

func AllDatumSlice() []Datum {
        ds := make([]Datum,0,8)
        ds = append(ds,NewIntDatum(1))
        ds = append(ds,NewUintDatum(1))
        ds = append(ds,NewFloat64Datum(28.0))
        ds = append(ds,NewDecimalDatum(NewDecFromStringForTest("72.5")))
        ds = append(ds,NewMysqlBitDatum([]byte{1,2,3,4,5,6,7,8,9}))
        ds = append(ds,NewTimeDatum(Time{Time: FromGoTime(time.Now()), Fsp: 6, Type: mysql.TypeTimestamp}))
        ds = append(ds,NewStringDatum("abcdefghijklmnopqrstuvwxyz"))
        ds = append(ds,NewBytesDatum([]byte("abcdefghijklmnopqrstuvwxyz")))
        return ds
}

func BenchmarkDatum(b *testing.B){
        ds := AllDatumSlice()
        for i:=0;i<b.N;i++ {
                foo1(ds[i%len(ds)])
        }
}

func BenchmarkDatumPoint(b *testing.B){
        ds := AllDatumSlice()
        for i:=0;i<b.N;i++ {
                foo2(&ds[i%len(ds)])
        }
}

result is:

~/code/goread/src/test2 ᐅ go version
go version go1.10.3 darwin/amd64
~/code/goread/src/test2 ᐅ go test -bench=. -v test_test.go
goarch: amd64
pkg: github.com/pingcap/tidb/types
BenchmarkDatum-8                100000000               10.6 ns/op
BenchmarkDatumPoint-8           200000000                7.91 ns/op
PASS
ok      github.com/pingcap/tidb/types   3.495s

[shenli]

LGTM
Good job!

[crazycs520]

@zz-jason PTAL

[zz-jason]

LGTM