The SQL execution plan is a critical factor that affects SQL statement performance. The stability of the SQL execution plans heavily influences the entire cluster's performance. If a relational database's optimizer chooses a wrong execution plan for a query, it usually has a negative impact on the system; for example, operations might take longer to respond or the database might get overloaded.
We've done a lot of work on optimizer stability for TiDB. However, SQL execution plans are affected by various factors. The execution plan may encounter unanticipated changes. As a result, the execution time might be too long.