Fix bit default value bug #7249

crazycs520 · 2018-08-02T06:53:22Z

What have you changed? (mandatory)

the problem:

mysql > create table t_bit (c1 bit(10) default 250, c2 int)
Query OK, 0 rows affected
Time: 0.109s
mysql > show create table t_bit
+-------+-------------------------------------------------------+
| Table | Create Table                                          |
+-------+-------------------------------------------------------+
| t_bit | CREATE TABLE `t_bit` (                                |
|       |   `c1` bit(10) DEFAULT b'111011111011111110111101',   |
|       |   `c2` int(11) DEFAULT NULL                           |
|       | ) ENGINE=InnoDB DEFAULT CHARSET=utf8 COLLATE=utf8_bin |
+-------+-------------------------------------------------------+
1 row in set
Time: 0.007s
mysql > insert into t_bit set c2=1;
(1690, "BIT value is out of range in '(10)'")

how I fix it
add DefaultValueBit to ColumnInfo to store the bit default value.

type ColumnInfo struct {
	...
	DefaultValueBit     []byte              `json:"default_bit"`
	...
}

compatibility
old -> new : Does not affect the old data.
new -> old : May have compatibility problem when the byte of default bit value >= 128. Because the old version always have the bug.

new:

mysql root@127.0.0.1:test> create table t_new (c1 int, c2 bit(10) default 128);
Query OK, 0 rows affected
mysql root@127.0.0.1:test> show create table t_new
+-------+-------------------------------------------------------+
| Table | Create Table                                          |
+-------+-------------------------------------------------------+
| t_new | CREATE TABLE `t_new` (                                |
|       |   `c1` int(11) DEFAULT NULL,                          |
|       |   `c2` bit(10) DEFAULT b'10000000'                    |
|       | ) ENGINE=InnoDB DEFAULT CHARSET=utf8 COLLATE=utf8_bin |
+-------+-------------------------------------------------------+
mysql root@127.0.0.1:test> insert into t_new set c1=1;
Query OK, 1 row affected
Time: 0.001s
mysql root@127.0.0.1:test> select * from t_new;
+----+--------+
| c1 | c2     |
+----+--------+
| 1  | 0x0080 |
+----+--------+

rollback to old:

mysql root@127.0.0.1:test> select * from t_new;
Reconnecting...
+----+--------+
| c1 | c2     |
+----+--------+
| 1  | 0x0080 |
+----+--------+
1 row in set
Time: 0.007s
mysql root@127.0.0.1:test> insert into t_new set c1=2;
(1690, "BIT value is out of range in '(10)'")

What is the type of the changes? (mandatory)

Bug fix (non-breaking change which fixes an issue)

How has this PR been tested? (mandatory)

unit test

Does this PR affect documentation (docs/docs-cn) update? (mandatory)

No

Does this PR affect tidb-ansible update? (mandatory)

No

Does this PR need to be added to the release notes? (mandatory)

No

Refer to a related PR or issue link (optional)

Benchmark result if necessary (optional)

Add a few positive/negative examples (optional)

…_default_value_bug

crazycs520 · 2018-08-02T08:27:32Z

@winkyao @zimulala @ciscoxll PTAL

crazycs520 · 2018-08-02T08:28:37Z

/run-all-tests

jackysp · 2018-08-02T08:54:22Z

model/model.go

@@ -66,6 +66,7 @@ type ColumnInfo struct {
 	Offset              int                 `json:"offset"`
 	OriginDefaultValue  interface{}         `json:"origin_default"`
 	DefaultValue        interface{}         `json:"default"`
+	DefaultValueBit     []byte              `json:"default_bit"`


Is it possible to use a uniform default value in cloumn info?

https://docs.google.com/document/d/17REO2MQ5v_AFOBE9ovehZDGlrtvhjCy3S1p7F1HWaSc/edit
This document explains the reason to do this way.

It is better to write down how to do it in the description of PR.

What's the problem

How to do it

Is there any compatibility problem

@ciscoxll done. PTAL

Will it be incompatible when rolling update TiDB?
As follows case:
On new TiDB, we builds a "add column" job , then we handle the DDL job on Old TiDB.

@crazycs520

@zimulala No. It is compatible.
if old tidb to handle job that created by new tidb, old tidb will ignore the DefaultValueBit .
I have done an experiment in this scene.

crazycs520 · 2018-08-03T04:56:20Z

/run-all-tests

crazycs520 · 2018-08-04T10:09:19Z

/run-unit-test

shenli · 2018-08-06T02:52:30Z

Should we modify coprocessor?

…_default_value_bug

crazycs520 · 2018-08-06T03:28:34Z

@shenli , currently we don't support pushdown the expr which contain bit column, So I think we don't need to modify coprocessor.

…_default_value_bug

zimulala · 2018-08-06T08:42:19Z

model/model.go

+			return nil
+		}
+		return types.ErrInvalidDefault.GenByArgs(c.Name)
+


Please remove this useless line.

zhexuany · 2018-08-06T09:56:36Z

/run-all-tests

crazycs520 · 2018-08-06T11:06:43Z

/run-unit-test

crazycs520 · 2018-08-10T00:57:08Z

@winkyao @zimulala @shenli PTAL

zz-jason · 2018-08-10T03:17:37Z

LGTM

…_default_value_bug

zhexuany · 2018-08-23T02:31:44Z

model/model.go

+	return nil
+}
+
+// GetDefaultValue gets the default value.


I feel like we need to add more comments. I understand that GetDefaultValue will return the default value of the column but I am more interested in the case handling logic.

GetDefaultValue just return the column's default value.
just use column.GetDefaultValue() instead of column.DefaultValue,
because the bit type default value will stored in DefaultValueBit field.

…_default_value_bug

crazycs520 · 2018-08-28T05:01:54Z

/run-all-tests

winoros · 2018-08-28T05:25:40Z

model/model.go

+// bit type default value will store in DefaultValueBit for fix bit default value decode/encode bug.
+func (c *ColumnInfo) GetDefaultValue() interface{} {
+	if c.Tp == mysql.TypeBit && c.DefaultValueBit != nil {
+		return string(c.DefaultValueBit)


should we use hack.String()?

winkyao · 2018-08-28T08:12:27Z

model/model.go

+func (c *ColumnInfo) SetDefaultValue(value interface{}) error {
+	c.DefaultValue = value
+	if c.Tp == mysql.TypeBit {
+		if v, ok := value.(string); ok {


Add more description here.

winkyao

Reset LGTM, please address comment

zimulala · 2018-08-28T12:17:32Z

model/model.go

+// GetDefaultValue gets the default value of the column.
+// Default value use to stored in DefaultValue field, but now,
+// bit type default value will store in DefaultValueBit for fix bit default value decode/encode bug.
+func (c *ColumnInfo) GetDefaultValue() interface{} {


Do we need to change all "c.DefaultValue" to "GetDefaultValue()"?

ye~ I have already changed it.

"if column.DefaultValue != nil" in column.go, the ColumnInfo in column.go is not the ColumnInfo in model.go

Do we need to replace "c.DefaultValue = types.ZeroDatetimeStr" with "SetDefaultValue()" in ddl_api.go?

oh...
ye...

…_default_value_bug

zimulala

LGTM

winkyao

LGTM

crazycs520 · 2018-08-30T07:29:22Z

/run-all-tests

…_default_value_bug

crazycs520 · 2018-08-30T08:56:50Z

/run-all-tests

crazycs520 added 3 commits August 2, 2018 14:43

fix bit default value bug

af00e81

Merge branch 'master' of https://github.com/pingcap/tidb into fix_bit…

d98444c

…_default_value_bug

update test

d8e001d

crazycs520 added the type/bugfix This PR fixes a bug. label Aug 2, 2018

jackysp reviewed Aug 2, 2018

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Merge branch 'master' of https://github.com/pingcap/tidb into fix_bit…

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…_default_value_bug

crazycs520 added 2 commits August 6, 2018 12:45

Merge branch 'master' of https://github.com/pingcap/tidb into fix_bit…

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…_default_value_bug

add comment

c1503eb

zimulala reviewed Aug 6, 2018

View reviewed changes

model/model.go Outdated

return nil

}

return types.ErrInvalidDefault.GenByArgs(c.Name)

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zimulala Aug 6, 2018

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Please remove this useless line.

refine code

f2b8579

zz-jason added status/LGT1 Indicates that a PR has LGTM 1. component/DDL-need-LGT3 labels Aug 10, 2018

Merge branch 'master' of https://github.com/pingcap/tidb into fix_bit…

619da40

…_default_value_bug

crazycs520 force-pushed the fix_bit_default_value_bug branch from 4b55313 to 619da40 Compare August 21, 2018 06:41

zhexuany reviewed Aug 23, 2018

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crazycs520 added 4 commits August 23, 2018 10:44

address comment

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Merge branch 'master' of https://github.com/pingcap/tidb into fix_bit…

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…_default_value_bug

Merge branch 'master' of https://github.com/pingcap/tidb into fix_bit…

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…_default_value_bug

Merge branch 'master' of https://github.com/pingcap/tidb into fix_bit…

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…_default_value_bug

winoros reviewed Aug 28, 2018

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winkyao reviewed Aug 28, 2018

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address comment

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zimulala reviewed Aug 28, 2018

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crazycs520 added 2 commits August 29, 2018 10:58

address comment

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Merge branch 'master' of https://github.com/pingcap/tidb into fix_bit…

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…_default_value_bug

zimulala reviewed Aug 29, 2018

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crazycs520 added status/LGT2 Indicates that a PR has LGTM 2. and removed status/LGT1 Indicates that a PR has LGTM 1. labels Aug 30, 2018

winkyao previously approved these changes Aug 30, 2018

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crazycs520 dismissed winkyao’s stale review via 16028de August 30, 2018 07:28

crazycs520 force-pushed the fix_bit_default_value_bug branch from b809f35 to 16028de Compare August 30, 2018 07:28

Merge branch 'master' of https://github.com/pingcap/tidb into fix_bit…

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…_default_value_bug

crazycs520 force-pushed the fix_bit_default_value_bug branch from 16028de to 5752ccb Compare August 30, 2018 08:28

Merge branch 'master' into fix_bit_default_value_bug

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ngaut and others added 3 commits August 30, 2018 23:37

Merge branch 'master' into fix_bit_default_value_bug

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Merge branch 'master' into fix_bit_default_value_bug

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Merge branch 'master' into fix_bit_default_value_bug

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crazycs520 merged commit 8d1acc2 into pingcap:master Aug 31, 2018

crazycs520 mentioned this pull request Feb 26, 2019

Fix affect of online DDL pingcap/tidb-binlog#466

Merged

you06 added the sig/sql-infra SIG: SQL Infra label Mar 4, 2020

Fix bit default value bug #7249

Fix bit default value bug #7249

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crazycs520 commented Aug 2, 2018 • edited Loading

What have you changed? (mandatory)

What is the type of the changes? (mandatory)

How has this PR been tested? (mandatory)

Does this PR affect documentation (docs/docs-cn) update? (mandatory)

Does this PR affect tidb-ansible update? (mandatory)

Does this PR need to be added to the release notes? (mandatory)

Refer to a related PR or issue link (optional)

Benchmark result if necessary (optional)

Add a few positive/negative examples (optional)

crazycs520 commented Aug 2, 2018

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crazycs520 Aug 22, 2018 • edited Loading

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crazycs520 commented Aug 30, 2018

crazycs520 commented Aug 30, 2018

crazycs520 commented Aug 2, 2018 •

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crazycs520 Aug 22, 2018 •

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