* better msg for create child table.

* just add one new line.

Hotfix/td 6272

Fix/query

 fix the show varibels case

merge from 2.0 into master

[TD-6336]<fix> insert into file cause core

[TD-6330]<fix> fix free error

[td-6182]fix windows join issue

[TD-6068] <test> fix the case ,add query after wal

[TD-6314]<test>:add test case for _block_dist()

[TD-6295][ci skip]<test>: Update performace test script for perfMonitor

[td-6315]fix group by tag+having in nested query issue

* better msg for create child table.

* just add one new line.

[TD-6311]<hotfix>: fix coredump for last_row query when cache_last_row

Feature/td 5838 master

Feature/m1