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 theUNION ALLstatement in some cases#7942
• Fix the stack overflow issue caused by wrong DDL Jobs#7959
• Add the slow log for theCommitoperation# 7983
• Fix the panic issue caused by the too largeLimitvalue#8004
• Support specifying theutf8mb4character set in theUSINGclause#8048
• Make theTRUNCATEbuilt-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 theSessionvariable to control whether_tidb_rowid允许writt吗en in#8126
• Fix the panic issue ofPhysicalProjectionin some cases#8154
• Fix the unstable results of theUnionstatement in some cases#8168
• Fix the issue thatNULLis not returned byvaluesin the non-Insertstatement#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• Fix the issue that the statistics module cannot clear the outdated data in some cases#8184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 ofexpression rewriterin some cases#8288
• Eliminate the extra columns generated by theUNION ORDER BYstatement#8307
• Support theadmin show next_row_idstatement#8274
• Fix the escape issue of special characters in theShow Create Tablestatement#8321
• Fix the unexpected errors in theUNIONstatement in some cases#8318
• Fix the issue that canceling a DDL job causes no rollback of a schema in some cases#8312
• Changetidb_max_chunk_sizeto a global variable#8333
• Add an upper bound to theScancommand 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 topd-ctlreading the Region key#1298#1299#1308
• Fix the issue that theregions/checkAPI returns the wrong result#1311
• Fix the issue that PD cannot restart join after a PD join failure#1279

TiKV

• Add theend-keylimit to thekv_scaninterface#3749
• Abandon themax-tasks-xxxconfiguration and addmax-tasks-per-worker-xxx#3093
• Fix theCompactFilesissue in RocksDB#3789