Add a JSON format for existing metrics like this.
```
{
"tags":
{
"metric":"thread_pool",
"name":"thrift-server-pool",
"type":"active_thread_num"
},
"unit":"number",
"value":3
}
```
I add a new JsonMetricVisitor to handle the transformation.
It's not to modify existing PrometheusMetricVisitor and SimpleCoreMetricVisitor.
Also I add
1. A unit item to indicate the metric better
2. Cloning tablet statistics divided by database.
3. Use white space to replace newline in audit.log
This CL mainly made the following modifications:
1. Delete Invalid method in Running Profile Class.
2. Move Memlimit Counter from blockmgr to fragment and add PeakMemUsage Counter
3. Fix the bug of buffer pool memlimit counter
4. Call compute_time_in_profile() before pretty_print() to show the _local_time_percent without child running profile
5. Add TransferThread ThreadToken count in AveThreadToken Counter
In the past, when we want to modify some BE configs, we have to modify be.conf and then restart BE.
This patch provides a way to modify configs in the type of 'threshold', 'interval', 'enable flag'
when BE is running without restarting it.
You can update a single config once by BE's http API: `be_host:be_http_port/api/update_config?config_name=new_value`
