* [TS-498]<test>: add a test case for HttpClientPoolUtil

* [TS-498]<fix>: fixed 'no sql input' bug

* throw exception when httpEntity is null

* [TS-498]<fix>: change taosd keepAlive to 30s
Co-authored-by: Nxywang <xywang@taosdata.com>

add tsClientMerge option to enable or disable client merge row and fix server duplicate row merge bug in skiplist

[TD-6264]<hotfix>:backport _block_dist() from 2.1 to 2.0 to fix core dump due to tbuf length limitation

* [TD-5062]<feature>: support partial update

[td-5407]<enhance>: add a local buffer for super table vgroup id list to improve the query performance.

[td-5418]<enhance>: change the refresh thread generate mechanism to reduce the number of refresh thread.