dumpling v5.+ may dump partitioned tables incorrectly because the result of tablesample is inordered

[lichunzhu]

Bug Report

Please answer these questions before submitting your issue. Thanks!

1. What did you do? If possible, provide a recipe for reproducing the error.

More details see pingcap/tidb#27349

2. What did you expect to see?

Dumpling dump data correctly.

3. What did you see instead?

Some data are lost and some are duplicated.

4. Versions of the cluster

   • Dumpling version (run dumpling -V):

     All v5.0.+, v5.1.+, v5.2.+

   • Source database version (execute SELECT version(); in a MySQL client):

     All v5.0.+, v5.1.+, v5.2.+

[lichunzhu]

We can sort pkVals by ourselves to avoid this problem.

dumpling/v4/export/dump.go

Line 726 in 4e012e5

return pkFields, pkVals, iter.Error()

[fubinzh]

/type bug

[fubinzh]

/severity major

[lichunzhu]

TiDB has already fixed this bug. We'd better ask users to upgrade to newer TiDB to avoid this bug. Close this issue now.