tidb-server v2.0.9

• Fix the issue caused by the empty statistics histogram #7927
• Fix the panic issue of the UNION ALL statement in some cases #7942
• Fix the stack overflow issue caused by wrong DDL Jobs #7959
• Add the slow log for the Commit operation #7983
• Fix the panic issue caused by the too large Limit value #8004
• Support specifying the utf8mb4 character set in the USING clause #8048
• Make the TRUNCATE built-in function support parameters of unsigned integer type #8069
• Fix the selectivity estimation issue of the primary key for the statistics module in some cases #8150
• Add the Session variable to control whether _tidb_rowid is allowed to be written in #8126
• Fix the panic issue of PhysicalProjection in some cases #8154
• Fix the unstable results of the Union statement in some cases #8168
• Fix the issue that NULL is not returned by values in the non-Insert statement #8179
• Fix the issue that the statistics module cannot clear the outdated data in some cases #8184
• Make the maximum allowed running time for a transaction a configurable option 8209
• Fix the wrong comparison algorithm of expression rewriter in some cases #8288
• Eliminate the extra columns generated by the UNION ORDER BY statement #8307
• Support the admin show next_row_id statement #8274
• Fix the escape issue of special characters in the Show Create Table statement #8321
• Fix the unexpected errors in the UNION statement in some cases #8318
• Fix the issue that canceling a DDL job causes no rollback of a schema in some cases #8312
• Change tidb_max_chunk_size to a global variable #8333
• Add an upper bound to the Scan command of ticlient, to avoid overbound scan #8309, #8310