get_query_ctx(hold query ctx map lock) ---> QueryCtx ---> runtime statistics mgr --->
runtime statistics mgr ---> allocate block memory ---> cancel query
memtracker will try to cancel query when memory is not available during allocator.
BUT the allocator is a foundermental API, if it call the upper API it may deadlock.
Should not call any API during allocator.
both global lock in fragment mgr should only protect the map logic, could not use it to protect cancel method.
fragment ctx cancel method should be protected by a lock.
query ctx cancel --> pipelinex fragment cancel ---> query ctx cancel will dead lock.
There are 2 potential reasons to cancel pipelineX query timeout.
Cancel fragment context first and set ready to execute will set cancel flag to false.
Dead lock.
Co-authored-by: yiguolei <yiguolei@gmail.com>Add a new class broadcastbufferholderqueue to manage holders
Using shared ptr to manage holders, not use ref and unref, it is too difficult to maintain.
using weak ptr as a lock between fragment execute thread and scanner thread, to solve the core problem in scanner's dctor to access scannode's profile.
