Launch a real-time instance
After you complete the development and publishing of a real-time task, you can launch the real-time instance in the Operation Center. This topic describes how to launch a real-time instance.
Entry points for launching real-time instances
Entry point 1: Launch a real-time instance from the real-time task entry
In the top navigation bar of the Dataphin homepage, choose Development > Task O&M.
In the left navigation pane, choose Task O&M > Stream Task to open the Stream Task page.
On the Stream Task page, click the start icon in the Actions
column of the target real-time task.
Entry point 2: Launch a real-time instance from the real-time instance entry
In the top navigation bar of the Dataphin homepage, choose Development > Task O&M.
In the left navigation pane, choose Instance O&M > Real-time Instance to open the Real-time Instance page.
On the Real-time Instance page, click the start icon in the Actions
column of the target real-time task.
Instructions for launching real-time instances
The methods for launching real-time instances vary depending on the compute engine, real-time instance type, and environment (development or production). The instructions are as follows:
Ververica Flink real-time engines
Launch a real-time computing instance
Production environment
In the Launch Real-time Instance dialog box, configure the launch information.
Parameter
Description
Launch Mode
Supports stateless launch and launch from a valid state.
Stateless Launch: Launches without any initial state. When launching statelessly, you can specify the time point from which the source table reads data. Setting a specific start time will make all source tables that support startTime read data from that moment.
ImportantCurrently, Log Service, Kafka, MySQL, MongoDB, and OceanBase support specifying the time point from which the source table reads data.
The parameter configuration in SQL jobs takes precedence over this specified start time.
Launch from Valid State: Launches from an existing valid state. You can select a Checkpoint or Savepoint from the dropdown menu. Only the 8 most recent valid states (Checkpoint or Savepoint) are available for selection. By default, the instance is launched from the latest state.
NoteIf the real-time instance does not have recent valid states, launching from a valid state is not supported.
Source Data Time Zone
The time zone of the source data source. This cannot be modified.
Data Timestamp
You can configure the data timestamp to assign values to time variables. Time variables are calculated based on the data timestamp. The default is the current day.
NoteReal-time integration tasks do not support data timestamp configuration.
NoteIf your project's compute source is Ververica Flink, the system will automatically determine whether your Ververica Flink compute source uses the latest interface. If it uses the latest interface, you also need to select either Run from Start Offset or Run from Latest State.
Run From Start Offset: Starts the instance based on the configured data reading time point and data timestamp.
Run From Latest State: Resumes running from the original state of the real-time instance.
Click Launch.
Development environment
In the Test Instance Parameter Configuration dialog box, configure specific values for the test instance parameters.
Parameter
Description
Specify Source Table Data Reading Time Point
Set the data reading time point. Setting a specific start time will make all source tables that support startTime read data from that moment.
ImportantCurrently, Log Service, Kafka, MySQL, MongoDB, and OceanBase support specifying the time point from which the source table reads data.
The parameter configuration in SQL jobs takes precedence over this specified start time.
Test Method
The test methods for Flink real-time tasks include log printing and writing to test tables:
If you select log printing, the test results are written to logs and no test table is generated.
If you select writing to test tables, the test results are not written to logs, but corresponding test tables are generated.
ImportantYou need to ensure that the test table already exists in the physical database (such as MySQL). Otherwise, the real-time instance will fail to run.
Input Table
No configuration required. This displays the input table name of the current real-time instance.
Data Timestamp
You can configure the data timestamp to assign values to time variables. Time variables are calculated based on the data timestamp. The default is the current day.
Whether the system reads from development tables or production test meta tables during test instance execution depends on the meta table configuration. To view meta table configurations, see Create and manage meta tables.
If the meta table's development environment test reading parameter is set to development table:
If the task uses
Project_Name_dev.meta_table_name, it reads from the development environment test meta table.If the task uses
Project_Name.meta_table_name, it reads from the production meta table. If you do not have permission to access the production environment test meta table, an error occurs. For information about how to apply for production environment test meta table permissions, see Apply for, renew, and relinquish table permissions.If the task uses
${Project_Name}.meta_table_nameor just meta_table_name, it reads from the development environment test meta table.
If the meta table's development environment test reading parameter is set to production table:
If the task uses
Project_Name_dev.meta_table_name, it reads from the development environment test meta table.If the task uses
Project_Name.meta_table_name, it reads from the production environment test meta table.If the task uses
${Project_Name}.meta_table_nameor just meta_table_name, it reads from the production environment test meta table.
If the meta table's development environment test writing parameter is set to other test tables:
If the task uses
Project_Name_dev.meta_table_name, it writes to the development test meta table.If the task uses
Project_Name.meta_table_name, it writes to the production environment test meta table. If you do not have permission to access the production environment test meta table, an error occurs. For information about how to apply for production environment test meta table permissions, see Apply for, renew, and relinquish table permissions.If the task uses
${Project_Name}.meta_table_nameor just meta_table_name, it writes to the development environment test meta table.
Click Launch.
Alibaba Blink real-time engine
Launch a real-time instance in development environment
In the Test Instance Parameter Configuration dialog box, configure specific values for the test instance parameters.
Parameter
Description
Data Reading Time Point
Sets the consumption time for reading source data.
Test Method
The test methods for Flink real-time tasks include log printing and writing to test tables:
If you select log printing, the test results are written to logs and no test table is generated.
If you select writing to test tables, the test results are not written to logs, but corresponding test tables are generated.
ImportantYou need to ensure that the test table already exists in the physical storage engine (such as HBase, Kafka, etc.). Otherwise, the real-time instance will fail to run.
Input Table
No configuration required. This displays the input table name of the current real-time instance.
Data Timestamp
You can configure the data timestamp to assign values to time variables. Time variables are calculated based on the data timestamp. The default is the current day.
Whether the system reads from development tables or production environment test meta tables during test instance execution depends on the meta table configuration. To view meta table configurations, see Create and manage meta tables.
If the meta table's development environment test reading parameter is set to development table:
If the task uses
Project_Name_dev.meta_table_name, it reads from the development environment test meta table.If the task uses
Project_Name.meta_table_name, it reads from the production meta table. If you do not have permission to access the production environment test meta table, an error occurs. For information about how to apply for production environment test meta table permissions, see Apply for, renew, and relinquish table permissions.If the task uses
${Project_Name}.meta_table_nameor just meta_table_name, it reads from the development environment test meta table.
If the meta table's development environment test reading parameter is set to production table:
If the task uses
Project_Name_dev.meta_table_name, it reads from the development environment test meta table.If the task uses
Project_Name.meta_table_name, it reads from the production environment test meta table.If the task uses
${Project_Name}.meta_table_nameor just meta_table_name, it reads from the production environment test meta table.
If the meta table's development environment test writing parameter is set to other test tables:
If the task uses
Project_Name_dev.meta_table_name, it writes to the development test meta table.If the task uses
Project_Name.meta_table_name, it writes to the production environment test meta table. If you do not have permission to access the production environment test meta table, an error occurs. For information about how to apply for production environment test meta table permissions, see Apply for, renew, and relinquish table permissions.If the task uses
${Project_Name}.meta_table_nameor just meta_table_name, it writes to the development environment test meta table.
Click Launch.
Launch a real-time instance in production environment
In the Launch Real-time Instance dialog box, configure the launch information.
Parameter
Description
Data Reading Time Point
Sets the consumption time for reading source data.
Data Timestamp
You can configure the data timestamp to assign values to time variables. Time variables are calculated based on the data timestamp. The default is the current day.
Click Launch.