When the physical memory of the process reaches 90% of the mem limit, trigger the load channel mgr to brush down
The default value of be.conf mem_limit is changed from 90% to 80%, and stability is the priority.
Fix deadlock in arena_locks in BufferPool::BufferAllocator::ScavengeBuffers and _lock in DebugString
1. Remove single load channel mem limit, only use load channel mgr mem limit
2. Default load channel mgr mem limit from 50% to 80%
3. load channel mgr add soft mem limit. When the soft limit is exceeded, other threads will not hang, only current thread triggers flush
4. When exceed load channel mgr mem limit, find a load channel with the largest mem usage, continue to find a tablet channel with the largest mem usage, and try to flush 1/3 of the mem usage of this tablet channel.
* [docs](function) add a series of date function documents
add docs for `hours_add`, `hours_sub`, `minutes_add`, `minutes_sub`,
`seconds_add`, `seconds_sub`, `years_sub`, `years_add`, `months_add`,
`months_sub`, `days_add`, `days_add`, `weeks_add`, `weeks_sub` functions.
tcmalloc/jemalloc allocator cache does not participate in the mem check as part of the process physical memory.
because new/malloc will trigger mem hook when using tcmalloc/jemalloc allocator cache, but it may not actually alloc physical memory, which is not expected in mem hook fail.
in addition:
The value of tcmalloc/jemalloc allocator cache is used as a mem tracker, the parent is the process mem tracker, which is updated every 1s.
Modify the process default mem_limit to 90%. expect mem tracker to effectively limit the memory usage of the process.
For debug purpose:
Add session variable skip_storage_engine_merge, when set to true, tables of aggregate key model and unique key model will be read as duplicate key model.
Add session variable skip_delete_predicate, when set to true, rows deleted with delete statement will be selected.
When FE send cancel rpc to BE, it does not notify the wait_for_start() thread, so that the fragment will be blocked and occupy the execution thread.
Add a max wait time for wait_for_start() thread. So that it will not block forever.
Add a new property called 'reserve_replica', which means you can
get a table with same partitions with the same replication num
as before the backup.
Co-authored-by: Stalary <stalary@163.com>
Co-authored-by: camby <104178625@qq.com>
