TiDB 2.0.9 Release Notes

On November 19, 2018, TiDB 2.0.9 is released. Compared with TiDB 2.0.8, this release has great improvement in system compatibility and stability.

TiDB

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Fix the issue that the statistics module cannot clear the outdated data in some cases #8184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

PD

Fix the issue that the PD server gets stuck caused by etcd startup failure #1267
Fix the issues related to pd-ctl reading the Region key #1298 #1299 #1308
Fix the issue that the regions/check API returns the wrong result #1311
Fix the issue that PD cannot restart join after a PD join failure #1279

TiKV

Add the end-key limit to the kv_scan interface #3749
Abandon the max-tasks-xxx configuration and add max-tasks-per-worker-xxx #3093
Fix the CompactFiles issue in RocksDB #3789