sync-diff-inspector: Doesn't check check constraints

[dveeden]

Bug Report

Please answer these questions before submitting your issue. Thanks!

1. What did you do?

Upstream:

create table t3 (id int primary key, check (id<10));

Downstream:

SET GLOBAL tidb_enable_check_constraint=ON;
create table t3 (id int primary key, check (id<20));

2. What did you expect to see?

Difference in the check constraint being reported

3. What did you see instead?

Comparing the table structure of ``test`.`t3`` ... equivalent

4. What version of TiDB are you using (tidb-server -V or run select tidb_version(); on TiDB)?

v8.0.0

5. which tool are you using?

sync_diff_inspector

6. what versionof tool are you using (pump -V or tidb-lightning -V or syncer -V)?

$ ./bin/sync_diff_inspector -V
App Name: sync_diff_inspector
Release Version: v8.1.0-1-g17af326
Git Commit Hash: 17af3262fc169d6a4ae3f6ece6ade4e49b24a804
Git Branch: master
UTC Build Time: 2024-05-24 09:30:01
Go Version: go1.22.3

[joechenrh]

From my perspective of view, check constraints will not affect the comparison results of the table data.
I wonder what scenario require comparison of these constraints.

[dveeden]

@joechenrh this indeed doesn't affect current table data. However it is part of the table structure and one might want to know if the table structure was copied correctly to the target database

[joechenrh]

@joechenrh this indeed doesn't affect current table data. However it is part of the table structure and one might want to know if the table structure was copied correctly to the target database

The simplest way is to directly check the ExprString in constraints #832

But this method cannot make some complex comparisons, for example, id > 10 and 10 < id.