This is an example of s3 hms_catalog:
```sql
CREATE CATALOG hms_catalog properties(
"type" = "hms",
"hive.metastore.uris"="thrift://localhost:9083",
"AWS_ACCESS_KEY" = "your access key",
"AWS_SECRET_KEY"="your secret key",
"AWS_ENDPOINT"="s3 endpoint",
"AWS_REGION"="s3-region",
"fs.s3a.paging.maximum"="1000");
```
All these params are necessary;
This feature is propsoed in [DSIP-1](https://cwiki.apache.org/confluence/display/DORIS/DSIP-001%3A+Java+UDF).
This PR support fixed-length input and output Java UDF. Phase I in DIP-1 is done after this PR.
To support Java UDF effeciently, I use no data copy in JNI call and all compute operations are off-heap in Java.
To achieve that, I use a UdfExecutor instead.
For users, a UDF class must have a public evaluate method.
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
1. Apache HDFS broker support HDFS HA and Hadoop kerberos authentication.
2. New Backup and Restore function. Use Fs Broker to backup your data to HDFS or restore them from HDFS.
3. Table-Level Privileges. Grant fine-grained privileges on table-level to specified user.
4. A lot of bugs fixed.
5. Performance improvement.
Add new features:
1. plugins of Ambari and k8s deploy
2. specified config 'priority_network' to solve some ip problems
Fix bugs:
fix bugs that rebalance does not work in some case.
fix count(*) from union stmt bug
fix some union stmt bugs
fix bugs when try to schema change a clone replica
