build1 distinct publisher
TiDB quietly turns primary-key ORDER BY into a TopN, and the fix is not in v8.5.7
Mercari's DBRE team found that on tables with a composite or non-integer primary key, TiDB reads every matching index entry and then sorts. The upstream fix is in master, not in the current LTS.
Publishers:engineering.mercari.com
Reality
- Evidence72
- Adoption38