types: Regard TypeNewDecimal as not a hasVariantFieldLength type.

[LittleFall]

What problem does this PR solve?

Issue Number: close #21804

Problem Summary:

Tiflash will check whether Decimal's flen is between 1 and 65. But TiDB enable will push down a Decimal constant with flen -1 from the environment parameter.

What is changed and how it works?

What's Changed:

When creating a decimal variable from Parameter, don't set it's flen to -1.

Other types in hasVariantFieldLength don't have this problem.

Related changes

• Need to cherry-pick to the release 4.0

Check List

Tests

• Unit test
  (will be added to tiflash repo)
• Integration test
• Manual test (add detailed scripts or steps below)

create table t (c_decimal decimal);
alter table t set tiflash replica 1; -- wait ready.
insert into t values (9), (10);
prepare s1 from 'select * from t where ? <= c_decimal';
set @v1 = 9.330;
execute s1 using @v1;
+-----------+
| c_decimal |
+-----------+
|        10 |
+-----------+

test for issue/8644

mysql> create table t(d decimal(3,2));
mysql> alter table t set tiflash replica 1; --wait ready

mysql> insert into t values (1.11), (2.222);
Query OK, 2 rows affected, 1 warning (0.03 sec) -- the warning is: Truncated incorrect DECIMAL value: '2.222'
mysql> insert into t values (33.3);
ERROR 1264 (22003): Out of range value for column 'd' at row 1

mysql> insert into t values ('1.11'), ('2.222');
Query OK, 2 rows affected, 1 warning (0.01 sec)
mysql> insert into t values ('33.3');
ERROR 1264 (22003): Out of range value for column 'd' at row 1

mysql> prepare s1 from 'insert t (d) values (?), (?)';
mysql> prepare s2 from 'insert t (d) values (?)';

mysql> set @a='1.11', @b='2.222', @c='33.3';
mysql> execute s1 using @a, @b;
Query OK, 2 rows affected, 1 warning (0.01 sec)
mysql> execute s2 using @c;
ERROR 1264 (22003): Out of range value for column 'd' at row 1

mysql> set @a=1.11, @b=2.222, @c=33.3;
mysql> execute s1 using @a, @b;
Query OK, 2 rows affected, 1 warning (0.02 sec)
mysql> execute s2 using @c;
ERROR 1264 (22003): Out of range value for column 'd' at row 1

Side effects

• N/A

Release note

• Fixed the issue that using prepare statement to cache execution plan caused tiflash to return Wrong precision.

[sre-bot]

No release note, Please follow https://github.com/pingcap/community/blob/master/contributors/release-note-checker.md

[sre-bot]

No release note, Please follow https://github.com/pingcap/community/blob/master/contributors/release-note-checker.md

[sre-bot]

No release note, Please follow https://github.com/pingcap/community/blob/master/contributors/release-note-checker.md

[LittleFall]

/run-check_release_note

[LittleFall]

/cc @eurekaka @dbjoa

[LittleFall]

/cc eurekaka,dbjoa

[LittleFall]

/run-all-tests

[LittleFall]

/label needs-cherry-pick-4.0

[LittleFall]

/label bug-fix

[ti-srebot]

These labels are not found bug-fix.

[lzmhhh123]

LGTM

[ti-srebot]

@LittleFall merge failed.

[LittleFall]

/run-all-tests

[lzmhhh123]

/merge

[ti-srebot]

/run-all-tests

[ti-srebot]

/run-all-tests

[lzmhhh123]

/merge

[ti-srebot]

Your auto merge job has been accepted, waiting for:

• 21922
• 21832

[ti-srebot]

/run-all-tests

[ti-srebot]

@LittleFall merge failed.

[lzmhhh123]

/merge

[ti-srebot]

Your auto merge job has been accepted, waiting for:

• 21903

[ti-srebot]

/run-all-tests

[ti-srebot]

/run-all-tests

[ti-srebot]

@LittleFall merge failed.

[ti-srebot]

cherry pick to release-4.0 in PR #21960