We make all MemTrackers shared, in order to show MemTracker real-time consumptions on the web.
As follows:
1. nearly all MemTracker raw ptr -> shared_ptr
2. Use CreateTracker() to create new MemTracker(in order to add itself to its parent)
3. RowBatch & MemPool still use raw ptrs of MemTracker, it's easy to ensure RowBatch & MemPool destructor exec
before MemTracker's destructor. So we don't change these code.
4. MemTracker can use RuntimeProfile's counter to calc consumption. So RuntimeProfile's counter need to be shared
too. We add a shared counter pool to store the shared counter, don't change other counters of RuntimeProfile.
Note that, this PR doesn't change the MemTracker tree structure. So there still have some orphan trackers, e.g. RowBlockV2's MemTracker. If you find some shared MemTrackers are little memory consumption & too time-consuming, you could make them be the orphan, then it's fine to use the raw ptr.
The new msg of limit exceed: "Memory exceed limit. %msg, Backend:%ip, fragment:%id Used:% , Limit:%. xxx".
This commit unifies the msg of 'Memory exceed limit' such as check_query_state, RETURN_IF_LIMIT_EXCEEDED and LIMIT_EXCEEDED.
2. add 2 new proc '/current_queries' and '/current_backend_instances' to monitor the current running queries.
3. add a manual compaction api on Backend to trigger cumulative or base compaction manually.
4. add Frontend config 'max_bytes_per_broker_scanner' to limit to bytes per one broker scanner. This is to limit the memory cost of a single broker load job
5. add Frontend config 'max_unfinished_load_job' to limit load job number: if number of running load jobs exceed the limit, no more load job is allowed to be submmitted.
6. a log of bug fixed
