Result Table

Updated on 2024-09-29 GMT+08:00

View PDF

Function

Flink SQL jobs write to the Doris result table.

Prerequisites

An enhanced datasource connection has been created for DLI to connect to Doris, so that jobs can run on the dedicated queue of DLI and you can set the security group rules as required.
- For details about how to set up an enhanced datasource connection, see Enhanced Datasource Connections.
- For details about how to configure security group rules, see Security Group Overview.
If MRS Doris is used, IP addresses of all hosts in the MRS cluster have been added to host information of the enhanced datasource connection.
For details, see Modifying Host Information.
Kerberos authentication is disabled for the cluster (the cluster is in normal mode)
After connecting to Doris as user admin, create a role with administrator permissions, and bind the role to the user.

Caveats

When you create a Flink OpenSource SQL job, set Flink Version to 1.15 in the Running Parameters tab. Select Save Job Log, and specify the OBS bucket for saving job logs.
Storing authentication credentials such as usernames and passwords in code or plaintext poses significant security risks. It is recommended using DEW to manage credentials instead. Storing encrypted credentials in configuration files or environment variables and decrypting them when needed ensures security. For details, see Flink OpenSource SQL Jobs Using DEW to Manage Access Credentials.
Kerberos authentication is disabled for the cluster (the cluster is in normal mode)
Doris table names are case sensitive.
When Doris of CloudTable is used, set the port number in the fenodes field to 8030, for example, xx:8030. In addition, enable ports 8030, 8040, and 9030 in the security group.
After HTTPS is enabled, add the following configuration parameters to the with clause for creating a table:
- 'doris.enable.https' = 'true'
- 'doris.ignore.https.ca' = 'true'
On the Running Parameters tab of the Flink job editing page, check Enable Checkpointing. Otherwise, data can be written to the Doris result table, and the delay in writing to Doris depends on the value set for Checkpoint Interval.

Syntax

create table dorisSource (
  attr_name attr_type 
  (',' attr_name attr_type)* 
 )
with (
  'connector' = 'doris',
  'fenodes' = 'FE_IP:PORT,FE_IP:PORT,FE_IP:PORT',
  'table.identifier' = 'database.table',
  'username' = 'dorisUsername',
  'password' = 'dorisPassword'
);

Parameter Description

Shared configuration

Parameter	Default Value	Mandatory	Parameter Type Description
fenodes	--	Yes	IP address and port number of the Doris FE. Use commas (,) to separate them for multiple instances. To obtain the port number, log in to FusionInsight Manager, choose Cluster > Services > Doris > Configurations, and search for http. Search for https instead if HTTPS is enabled.
table.identifier	--	Yes	Doris table name, for example, db.tbl.
username	--	Yes	User name for accessing Doris.
password	--	Yes	Password for accessing Doris.
sink.label-prefix	""	Yes	Label prefix used for Stream load import. It must be globally unique in two-phase commit (2pc) scenarios to ensure Flink's EOS semantics.
sink.enable-2pc	TRUE	No	Whether to enable 2pc for ensuring Exactly-Once semantics. The default value is true. Refer to this link for more information on 2pc.
sink.check-interval	10000	No	Interval for checking exceptions during loading.
sink.max-retries	3	No	Maximum number of retries when writing records to the database fails.
sink.buffer-size	256 * 1024	No	Buffer size for caching data during Stream load.
sink.buffer-count	3	No	Buffer count for caching data during Stream load.
sink.enable-delete	TRUE	No	Whether to enable deletion. This option requires batch deletion to be enabled for the Doris table (default in Doris 0.15 or later for Unique model only).
sink.properties.*	--	No	Import parameters for Stream load. For example, 'sink.properties.column_separator' = ',' defines the column separator, and 'sink.properties.escape_delimiters' = 'true' treats special characters as separators, where '\x01' is converted to binary 0x01. JSON format import 'sink.properties.format' = 'json' 'sink.properties.read_json_by_line' = 'true'

Example

In this example, data is read from the DataGen data source and written to the Doris result table.

Create an enhanced datasource connection in the VPC and subnet where Doris locates, and bind the connection to the required Flink elastic resource pool. For details, see Enhanced Datasource Connections. Add MRS host information for the enhanced datasource connection. For details, see Modifying Host Information.
Set Doris security groups and add inbound rules to allow access from the Flink queue. Test the queue connectivity based on the Doris address. If the connection passes the test, it is bound to the queue.
For details, see Testing Address Connectivity.

Create a Doris table by referring to MRS Doris Usage Guide. The creation statement is as follows:

CREATE TABLE IF NOT EXISTS dorisdemo
(
  `user_id` varchar(10) NOT NULL,
  `city` varchar(10),
  `age` int,
  `gender` int
)
DISTRIBUTED BY HASH(`user_id`) BUCKETS 10

Create a Flink OpenSource SQL job. Enter the following job script and submit the job. The job script uses DataGen as the data source and writes data to as a Doris result table.

create table student_datagen_source(
  `user_id` String NOT NULL,
  `city` String,
  `age` int,
  `gender` int
) with (
  'connector' = 'datagen',
  'rows-per-second' = '1',
  'fields.user_id.kind' = 'random',
  'fields.user_id.length' = '7', 
  'fields.city.kind' = 'random',
  'fields.city.length' = '7'
);


CREATE TABLE dorisDemo (
  `user_id` String NOT NULL,
  `city` String,
  `age` int,
  `gender` int
) with (
  'connector' = 'doris',
  'fenodes' = 'FE_IP:PORT',
  'table.identifier' = 'demo.dorisdemo',
  'username' = 'dorisUser',
  'password' = 'dorisPassword',
  'sink.label-prefix' = 'demo',
  'sink.enable-2pc' = 'true',
  'sink.buffer-count' = '10'
);

insert into dorisDemo select * from student_datagen_source

Check whether data is successfully written to the Doris result table.