This PR is to add inPredicate support to delete statement,
and add max_allowed_in_element_num_of_delete variable to
limit element num of InPredicate in delete statement.
StorageEngine::open just return a very vague status info when failed,
we have to check logs to find out the root reason, and it's not
convenient to check logs if we run unit tests in CI dockers.
It would be better to return more detailed failure info to point out
the root reason, for example, it may return error status with message
"file descriptors limit is too small".
We can observe the workload of BE, and also it's a way to check
whether there is any problem in BE, like some container increase
too large and lead to OOM.
This patch add the following metrics:
```
Name Description
rowset_count_generated_and_in_use The total count of rowset id generated and in use since BE last start
unused_rowsets_count The total count of unused rowset waiting to be GC
broker_count The total count of brokers in management
data_stream_receiver_count The total count of data stream receivers in management
fragment_endpoint_count The total count of fragment endpoints of data stream in management, should always equal to data_stream_receiver_count
active_scan_context_count The total count of active scan contexts
plan_fragment_count The total count of plan fragments in executing
load_channel_count The total count of load channels in management
result_buffer_block_count The total count of result buffer blocks for queries, each block has a limited queue size (default 1024)
result_block_queue_count The total count of queues for fragments, each queue has a limited size (default 20, by config::max_memory_sink_batch_count)
routine_load_task_count The total count of routine load tasks in executing
small_file_cache_count The total count of cached small files' digest info
stream_load_pipe_count The total count of stream load pipes, each pipe has a limited buffer size (default 1M)
tablet_writer_count The total count of tablet writers
brpc_endpoint_stub_count The total count of brpc endpoints
```
In Doris, one block has 1024 rows.
1. If the previous ScanKey scan rows multiple blocks,
and also the final block has 1024 rows just right.
2. The current ScanKey scan rows with number less than one block.
Under the two conditions, if not seek block, the position of prefix shortkey columns is wrong.
NOTE: This patch would modify all Backend's data.
And this will cause a very long time to restart be.
So if you want to interferer your product environment,
you should upgrade backend one by one.
1. Refactoring be is to clarify the structure the codes.
2. Use unique id to indicate a rowset.
Nameing rowset with tablet_id and version will lead to
many conflicts among compaction, clone, restore.
3. Extract an rowset interface to encapsulate rowsets
with different format.
