config: disable query feedback by default. (pingcap#20179)

tikv: remove the update leader backoff (pingcap#17541) (pingcap#19764)

* cherry pick pingcap#17541 to release-3.0

Signed-off-by: ti-srebot <ti-srebot@pingcap.com>

Revert "*: using standard error to replace terror (pingcap#19425)" (p…

…ingcap#19945)

executor: reset kvRange in TableReaderExec.Close (pingcap#19447) (pin…

…gcap#19470)

Signed-off-by: ti-srebot <ti-srebot@pingcap.com>

planner: invalidate cached plan if no UnionScan for tables that need …

…it (pingcap#15429) (pingcap#19274)

Co-authored-by: Kenan Yao <cauchy1992@gmail.com>

tikv: force disable local latches (pingcap#18886)

util: fix a encode bug causes the wrong result of ... (pingcap#18855) (…

…pingcap#18866)

brie: set default config for backup and restore (pingcap#18774)

tikv: fix wrong cherry-pick 3.0 (pingcap#18292)

cherry pick pingcap#18268 to release-4.0 (pingcap#18276)

Signed-off-by: ti-srebot <ti-srebot@pingcap.com>

Co-authored-by: Han Fei <hanfei19910905@gmail.com>
Co-authored-by: jebter <jebter@126.com>