enh(query): opt group by tag perf.

refactor:do some internal refactor to optimize the query performance.

fix: fix kill query crash issue

fix: change schema-less describtion to reduce ambiguity

fix: taos-sql/functions document error

fix(stream): memory leak

fix(stream):Defects Tracking, delete log

enh: do coverity scan

docs: fix 'terminate a tuery' chapter

fix: converity scan problem

fix(tmq): push msg

feat: support case when operator

os: Mac change service name

fix:sml core dump if insert quickly because of spin lock destroy

Fix/zhiqiang wang/td 19488 memory param over

fix: close merge tree for each file set