This function applies only to clusters of MRS 3.5.0 and later versions.

Scenario

You can configure inspection rules for Doris SQL statements on MRS Manager and set rule parameters based on your needs.

Prerequisites

The node to be connected to the Doris database can communicate with the MRS cluster.
FE and BE instances are normal.
The MySQL client has been installed.

Constraints

A SQL inspection rule is automatically applied in 5 minutes.
Interception and blocking rules will interrupt SQL queries, so you need to set parameters of these rules properly based on the site requirements.

Procedure

Create a user with the Doris administrator permissions to connect to the Doris service.
1. Log in to MRS Manager as user admin, choose System > Permission > Role, click Create Role, set the following parameters, and click OK.
  - Role Name: Enter a role name, for example, dorisrole.
  - Configure Resource Permission: In the resource permission list, choose Name of the target cluster > Doris and select Doris Administrator Permission according to the permission you need. Click Doris Read and Write Privileges and select Select, Drop, Load, Alter, Create, and Grant permission in the internal row.
  Figure 1 Creating a Doris role
2. Click User. If Kerberos authentication is enabled for the cluster (the cluster is in security mode), add a human-machine user. If Kerberos authentication is disabled for the cluster (the cluster is in normal mode), add a machine-machine user. Bind the user to the created role.
3. Change the initial password.
Log in to MRS Manager as a user with the Manager_administrator and Manager_viewer permissions and choose Cluster > SQL Inspector.
Add a rule for Doris by referring to Adding an SQL Inspection.
For details about the rules supported by the Doris SQL engine, see MRS SQL Inspection Rules.

For example, add the static_0001 rule while setting the threshold to 1 for the Hint action and 6 for the Intercept action. This rule detects a SQL statement that contains more than one count distinct.

Figure 2 Adding a Doris SQL inspection rule
Log in to the node where MySQL is installed and connect to the Doris database.
If Kerberos authentication (security mode) has been enabled for the cluster, run the following commands to connect to the Doris database:

export LIBMYSQL_ENABLE_CLEARTEXT_PLUGIN=1
- Directly connect to the FE node to access the Doris database.
  mysql -uDatabase login username -p -PConnection port for FE queries -hIP address of the Doris FE instance
  
  Enter the password for logging in to the database.
- Connect the DBalancer service. DBalancer connects to the FE node to access the Doris database based on the configured policy.
  mysql -uDatabase login user -p -PTCP access port of DBalancer -hIP address of the Doris DBalancer instance
  
  Enter the password for logging in to the database.
- The database login user is the user created in 1 and has the Doris administrator permission.
- To obtain the query connection port of the Doris FE instance, you can log in to MRS Manager, choose Cluster > Services > Doris > Configurations, and query the value of query_port of the Doris service.
- To obtain the query connection port of the Doris FE instance, you can log in to MRS Manager, choose Cluster > Services > Doris > Configurations, and query the value of balancer_tcp_port of the Doris service.
- To obtain the IP address of the Doris FE or DBalancer instance, log in to MRS Manager of the MRS cluster and choose Cluster > Services > Doris > Instances to view the service IP address of any FE or DBalancer instance.
- You can also use the MySQL connection software or Doris web UI to connect to the database.
Enter the password of the dorisuser user after running the command.

Check the configured SQL inspection rules.

use __internal_schema;

select * from sqldefend_rule;

+-------------+----------+--------------------+--------+-----------------+------+------+------+
| rule_name   | is_group | group_or_user_name | action | threshold_value | p_1  | p_2  | p_3  |
+-------------+----------+--------------------+--------+-----------------+------+------+------+
| static_0001 |        1 | A                  |      1 |               3 | NULL | NULL | NULL |
| static_0001 |        1 | A                  |      2 |               2 | NULL | NULL | NULL |
+-------------+----------+--------------------+--------+-----------------+------+------+------+

Create a database and switch to the database.
create database test;

use test;
Create tables t1, t2, and t3.
create table if not exists t1(id int) engine=olap distributed by hash(id);

create table if not exists t2(id int) engine=olap distributed by hash(id);

create table if not exists t3(id int) engine=olap distributed by hash(id);
Check whether the static_0001 rule has taken effect.
select count(distinct id) from t1 except select count(distinct id) from t2 intersect select count(distinct id) from t3 union all select count(distinct id) from t1 except select count(distinct id) from t2 intersect select count(distinct id) from t3;

The number of count distinct in this statement exceeds the threshold configured in 3.
- If the number of count distinct is greater than the threshold for a hint but is no more than the threshold for interception, the statement will be executed successfully. Run the following command to view the detailed prompt information:
  show warnings;
```
+----------------------------------------------+-------------+------------------------------------------------------------------------------------+
| QueryId                                      | RuleType    | Message                                                                            |
+----------------------------------------------+-------------+------------------------------------------------------------------------------------+
| stmt[306, 887f43753bb749c9-b6ed36350f9454a8] | STATIC_RULE | static_0001 number of count(distinct) in the query 6 more than the allowed limit 1 |
+----------------------------------------------+-------------+------------------------------------------------------------------------------------+
```
  887f43753bb749c9-b6ed36350f9454a8 indicates the query ID. To view the SQL statement corresponding to the message, run the following command:
  
  select * from query_history where query_id='887f43753bb749c9-b6ed36350f9454a8';
- If number of count distinct is greater than the interception threshold, the statement will be interrupted and fail to be executed and the following information is displayed:
```
ERROR ... detailMessage = static_0001 number of count(distinct) in the query 7 more than the allowed limit 6
```
  show warnings;
  
  The statement output is empty.
```
Empty set (0.00 sec)
```
- If the action set in the SQL inspection rule is Block, the following information may be displayed:
```
ERROR ... detailMessage = running_0001 Num of result rows num reaches the fuse threshold(1000), so cancel the output
```
- You can query SQL inspection details in /var/log/Bigdata/doris/fe/fe.log and /var/log/Bigdata/audit/doris/fe/fe.audit.log.

Configuring Doris SQL Inspection

Scenario

Prerequisites

Constraints

Procedure