Configuring a Job for Synchronizing Data from Oracle to Doris (Internal Test)

Supported Source and Destination Database Versions

**Table 1** Supported database versions
Source Database	Destination Database
Oracle database (versions 10, 11, 12, and 19)	Doris (Doris1.2 and Doris2.0)

Database Account Permissions

Before you use DataArts Migration for data synchronization, ensure that the source and destination database accounts meet the requirements in the following table. The required account permissions vary depending on the synchronization task type.

**Table 2** Database account permissions
Type	Required Permissions
Source database connection account	The account must have the permissions to archive logs, query tables, and parse logs of the Oracle database. For details about how to grant the permissions, see How Do I Grant the Log Archiving, Query, and Parsing Permissions of an Oracle Data Source?
Destination database connection account	The account must have the following permissions for each table in the destination database: INSERT, SELECT, UPDATE, DELETE, CONNECT, and CREATE.

You are advised to create independent database accounts for DataArts Migration task connections to prevent task failures caused by password modification.
After changing the account passwords for the source or destination databases, modify the connection information in Management Center as soon as possible to prevent automatic retries after a task failure. Automatic retries will lock the database accounts.

Supported Synchronization Objects

The following table lists the objects that can be synchronized using different links in DataArts Migration.

**Table 3** Synchronization objects
Type	Note
Synchronization objects	The following DML operations can be synchronized: INSERT, UPDATE, and DELETE. The DDL operation of adding columns can be synchronized. Only primary key tables can be synchronized. Views, foreign keys, stored procedures, triggers, functions, events, virtual columns, unique constraints, unique indexes, foreign key indexes, and check constraints cannot be synchronized. Table structures, common indexes, constraints (primary key, null, and non-null), and comments can be synchronized during automatic table creation.

Notes

In addition to the constraints on supported data sources and versions, connection account permissions, and synchronization objects, you also need to pay attention to the notes in the following table.

**Table 4** Notes
Type	Constraint
Database	The names of the source databases, tables, and fields cannot contain periods (.), hyphens (-), or non-ASCII characters. You are advised to use common characters to avoid a failure. Object names in the destination database must meet the following requirements: The table name can contain a maximum of 64 characters and must start with a letter. Only letters, digits, underscores (_), and hyphens (-) are allowed. The field name can contain a maximum of 255 characters. You are advised to use common characters. Do not use special characters such as Chinese characters.
Usage	General: During real-time synchronization, the IP addresses, ports, accounts, and passwords cannot be changed. It is recommended that Oracle archive logs be retained for more than three days. Otherwise, the task may fail because logs cannot be obtained. In some special cases, data may be inconsistent or lost. resetlogs operations cannot be performed on the source Oracle database. Otherwise, data cannot be synchronized, and the job cannot be recovered. The username (schema name) of the source Oracle database cannot be changed, neither by modifying the USER$ dictionary table in versions earlier than 11.2.0.2 nor by running the ALTER USER username RENAME TO new_username command in 11.2.0.2 and later versions. If the source is an Oracle database, CLOB, NCLOB, and BLOB data cannot be migrated. Oracle RAC clusters cannot be the source. If the source is an Oracle database, it can connect to the standby Oracle database of a single instance but cannot connect to a standby database in an RAC cluster. Only archive logs can be read from the standby database, and standby logs cannot be read from the standby database. When connecting to the standby database, you are advised to configure scheduled archiving to reduce the data synchronization latency. It is recommended that the network bandwidth be greater than 100 Mbit/s. Full synchronization phase: During task startup and full data synchronization, do not perform DDL operations on the source database. Otherwise, the task may fail. Incremental synchronization phase: DML operations INSERT, UPDATE, and DELETE can be synchronized. The DDL operation of adding columns can be synchronized. Mixed partitioned tables are not supported. When data in the external partition of a mixed partitioned table changes, no DML log is generated. As a result, the change information cannot be obtained during incremental data synchronization, which may cause data inconsistency. The table name and column name can contain a maximum of 30 characters. Oracle LogMiner is used to read Oracle logs. The table name and column name can contain a maximum of 30 characters. For details, see Using LogMiner to Analyze Redo Log Files. During incremental startup, select a time point. Ensure that the Oracle database is in the same time zone as the host where the database is located to ensure the accuracy of the incremental time point. Distributed transactions (XA transactions) and PARALLEL DML on Oracle cannot be incrementally synchronized. During incremental synchronization, Oracle extended characters are not supported. The standard character set cannot parse Oracle customized extended characters. During incremental synchronization, triggers cannot be synchronized or migrated. You must disable the triggers on the destination Oracle database. Data with foreign key constraints cannot be incrementally synchronized or migrated. Data imported to the source database using Oracle Data Pump cannot be incrementally synchronized or migrated. Troubleshooting: If any problem occurs during task creation, startup, full synchronization, incremental synchronization, or completion, rectify the fault by referring to FAQs.
Other	If the length of a table structure in the Oracle database exceeds 65,535 bytes, the synchronization may fail. The length of a table structure is the total length of all columns. The length of the char or varchar2 type is related to the code. During incremental synchronization from the PDB database, all PDBs must be enabled due to restrictions of Oracle LogMiner. During incremental synchronization to Oracle 12.2 or later, the table name or column name cannot contain more than 30 characters due to restrictions of Oracle LogMiner. For a full and incremental job or an incremental job that migrates data from an Oracle database, if you want to synchronize tables in the PDB database, you need to enter the username and password of the CDB database in the Oracle connection. This is because Oracle logs are stored in the CDB database and Oracle LogMiner can run only in the CDB database. To delete a table using DDL, run the drop table test_table_name purge command. Deleting a table in the Oracle database is a high-risk operation by default. When the drop table test_table_name command is executed, the Oracle database converts the command to rename table test_table_name as xxxxx. That is, the table is renamed as a table to be processed in the Oracle temporary tablespace. The original table is not deleted, and DataArts Migration ignores the syntax by default. The data deletion statement drop table test_table_name purge of the Oracle database completely deletes the table. DataArts Migration automatically identifies and delivers the deleted table to the downstream. Full and incremental synchronization does not support hidden columns (UNUSED, INVISIBLE). Tables with no primary keys are not supported. Data control language (DCL) operations are not supported. Consecutive RENAME TABLE operations cannot be synchronized or migrated. Otherwise, the task may fail. Global temporary tables cannot be synchronized or migrated (the task is running properly). Tables that contain default value functions cannot be synchronized or migrated. Otherwise, data will be inconsistent. Tables with default values that contain expressions cannot be synchronized or migrated. Foreign tables cannot be synchronized or migrated. Compute columns and encrypted columns cannot be synchronized or migrated. Virtual private databases (VPDs) cannot be synchronized or migrated. Jobs created by dbms_scheduler and dbms_job cannot be synchronized or migrated. Schema name changes cannot be synchronized or migrated. Nested tables cannot be synchronized or migrated. Otherwise, an error will occur. Materialized views cannot be synchronized or migrated. DDL operations with attribute names that contain keywords or special characters cannot be synchronized or migrated. ROWID change operations (such as split partition, table move, table shrink, and move partition key) are not supported. Otherwise, data inconsistency or task failures may occur. The Secure Sockets Layer (SSL) encryption transmission mode is not supported. The Oracle Label Security mode is not supported. Doris cannot use a string as the primary key, even if as one of the fields in a composite primary key.

Procedure

This section uses real-time synchronization from Oracle to Doris as an example to describe how to configure a real-time data migration job. Before that, ensure that you have read the instructions described in Check Before Use and completed all the preparations.

Create a real-time migration job by following the instructions in Creating a Real-Time Migration Job and go to the job configuration page.
Select the data connection type. Select Oracle for Source and Doris for Destination.

Figure 1 Selecting the data connection type
Select a job type. The default migration type is Real-time. The migration scenario is Entire DB.

Figure 2 Setting the migration job type

For details about synchronization scenarios, see Synchronization Scenarios.
Configure network resources. Select the created Oracle and Doris data connections and the migration resource group for which the network connection has been configured.

Figure 3 Selecting data connections and a migration resource group

If no data connection is available, click Create to go to the Manage Data Connections page of the Management Center console and click Create Data Connection to create a connection. For details, see Configuring DataArts Studio Data Connection Parameters.

If no migration resource group is available, click Create to create one. For details, see Buying a DataArts Migration Resource Group Incremental Package.
Configure source parameters.

Select the Oracle databases and tables to be migrated.
Figure 4 Selecting databases and tables

Both databases and tables can be customized. You can select one database and one table, or multiple databases and tables.

Configure destination parameters.

Set Database and Table Matching Policy.
- Database Matching Policy
  - Same name as the source database: Data will be synchronized to the Doris database with the same name as the source PostgreSQL database.
  - Custom: Data will be synchronized to the Doris database you specify.
- Table Matching Policy
  - Same name as the source table: Data will be synchronized to the Doris table with the same name as the source PostgreSQL table.
  - Custom: Data will be synchronized to the Doris table you specify.
    Figure 5 Database and table matching policy in the entire database migration scenario
    
    When you customize a matching policy, you can use built-in variables #{source_db_name} and #{source_table_name} to identify the source database name and table name. The table matching policy must contain #{source_table_name}.

Set Doris parameters.

You can configure the advanced parameters in the following table to enable some advanced functions.

**Table 5** Doris advanced parameters
Parameter	Type	Default Value	Unit	Description
doris.request.connect.timeout.ms	int	30000	ms	Doris connection timeout interval
doris.request.read.timeout.ms	int	30000	ms	Doris read timeout interval
doris.request.retries	int	3	-	Number of retries upon a Doris request failure
sink.max-retries	int	3	-	Maximum number of retries upon a data writing failure
sink.batch.interval	string	1s	h/min/s	Interval at which an asynchronous thread writes data
sink.enable-delete	boolean	true	-	Whether to enable the deletion function. If this function is disabled, data deleted from the source will not be deleted from the destination.
sink.batch.size	int	20000	-	Maximum number of rows that can be written (inserted, updated, or deleted) at a time
sink.batch.bytes	long	10485760	bytes	Maximum number of bytes that can be written (inserted, updated, or deleted) at a time
logical.delete.enabled	boolean	false	-	Whether to enable logical deletion. If this function is enabled, the destination must contain the deletion flag column. When data is deleted from the source database, the corresponding data in the destination database will not be deleted. Instead, the deletion flag column is set to true, indicating that the data is not contained at the source.
logical.delete.column	string	logical_is_deleted	-	Name of the logical deletion column. The default value is logical_is_deleted. You can customize the value.
sink.keyby.mode	string	pk	-	Partitioning mode when concurrent writes are performed on Doris. Default value: pk (primary key). If the source is Kafka, and it does not have a primary key, select table to partition data by table name.
doris.sink.flush.tasks	int	1	-	Number of concurrent flushes of a single TaskManager
sink.properties.format	string	json	-	Data format used by Stream Load. The value can be json or csv.
sink.properties.Content-Encoding	string	-	-	Compression format of the HTTP header message body. Currently, only CSV files can be compressed, and the .gzip format is supported.
sink.properties.compress_type	string	-	-	File compression format. Currently, only CSV files can be compressed. The .gz, .lzo, .bz2, .lz4, .lzop, and .deflate compression formats are supported.

Refresh and check the mapping between the source and destination tables. In addition, you can modify table attributes, add additional fields, and use the automatic table creation capability to create tables in the destination Doris database.

Figure 6 Mapping between source and destination tables
Click to enlarge

Edit additional fields: Click Additional Field in the Operation column to add custom fields to the destination Doris table. For a new table, you can add additional fields to the existing fields in the source table. You can customize the field name, select the field type, and enter the field value.

Field Name: name of the new field in the destination Doris table
Field Type: type of the new field in the destination Doris table
(Optional) Field Type Length: length of the new field type in the destination Doris table

Field Value: value source of the new field in the destination Doris table

**Table 6** Additional field value obtaining mode
Type	Example
Constant	Any character
Built-in variable	Source host IP address: source.host Source schema name: source.schema Source table name: source.table Destination schema name: target.schema Destination table name: target.table Source data change time: source.event.timestamp
Source table field	Any field in the source table Do not change the name of the source table field when the job is running. Otherwise, the job may be abnormal.
UDF	substring(#col, pos[, len]): obtains a substring of a specified length from the source column name. The substring range is [pos, pos+len). date_format(#col, time_format[, src_tz, dst_tz]): formats the source column name based on a specified time format. The time zone can be converted using src_tz and dst_tz. now([tz]): obtains the current time in a specified time zone. if(cond_exp, str1, str2): returns str1 if the condition expression cond_exp is met and returns str2 otherwise. concat(#col[, #str, ...]): concatenates multiple parameters, including source columns and strings. from_unixtime(#col[, time_format]): formats a Unix timestamp based on a specified time format. unix_timestamp(#col[, precision, time_format]): converts a time into a Unix timestamp of a specified time format and precision.

Automatic table creation: Click Auto Table Creation to automatically create tables in the destination database based on the configured mapping policy. After the tables are created, Existing table is displayed for them.
- DataArts Migration supports only automatic table creation. You need to manually create databases and schemas at the destination before using this function.
- For details about the field type mapping for automatic table creation, see Field Type Mapping.

Configure task parameters.

**Table 7** Task parameters
Parameter	Description	Default Value
Execution Memory	Memory allocated for job execution, which automatically changes with the number of CPU cores	8GB
CPU Cores	Value range: 2 to 32 For each CPU core added, 4 GB execution memory and one concurrency are automatically added.	2
Maximum Concurrent Requests	Maximum number of jobs that can be concurrently executed. This parameter does not need to be configured and automatically changes with the number of CPU cores.	1
Auto Retry	Whether to enable automatic retry upon a job failure	No
Maximum Retries	This parameter is displayed when Auto Retry is set to Yes.	1
Retry Interval (Seconds)	This parameter is displayed when Auto Retry is set to Yes.	120s
Write Dirty Data	Whether to record dirty data. By default, dirty data is not recorded. If there is a large amount of dirty data, the synchronization speed of the task is affected. No: Dirty data is not recorded. This is the default value. Dirty data is not allowed. If dirty data is generated during the synchronization, the task fails and exits. Yes: Dirty data is allowed, that is, dirty data does not affect task execution. When dirty data is allowed and its threshold is set: If the generated dirty data is within the threshold, the synchronization task ignores the dirty data (that is, the dirty data is not written to the destination) and is executed normally. If the generated dirty data exceeds the threshold, the synchronization task fails and exits. NOTE: Criteria for determining dirty data: Dirty data is meaningless to services, is in an invalid format, or is generated when the synchronization task encounters an error. If an exception occurs when a piece of data is written to the destination, this piece of data is dirty data. Therefore, data that fails to be written is classified as dirty data. For example, if data of the VARCHAR type at the source is written to a destination column of the INT type, dirty data cannot be written to the migration destination due to improper conversion. When configuring a synchronization task, you can configure whether to write dirty data during the synchronization and configure the number of dirty data records (maximum number of error records allowed in a single partition) to ensure task running. That is, when the number of dirty data records exceeds the threshold, the task fails and exits.	No
Dirty Data Policy	This parameter is displayed when Write Dirty Data is set to Yes. The following policies are supported: Do not archive: Dirty data is only recorded in job logs, but not stored. Archive to OBS: Dirty data is stored in OBS and printed in job logs.	Do not archive
Write Dirty Data Link	This parameter is displayed when Dirty Data Policy is set to Archive to OBS. Only links to OBS support dirty data writes.	N/A
Dirty Data Directory	OBS directory to which dirty data will be written	N/A
Dirty Data Threshold	This parameter is only displayed when Write Dirty Data is set to Yes. You can set the dirty data threshold as required. NOTE: The dirty data threshold takes effect for each concurrency. For example, if the threshold is 100 and the concurrency is 3, the maximum number of dirty data records allowed by the job is 300. Value -1 indicates that the number of dirty data records is not limited.	100
Custom attributes	You can add custom attributes to modify some job parameters and enable some advanced functions. For details, see Job Performance Optimization.	N/A

Submit and run the job.

After configuring the job, click Submit in the upper left corner to submit the job.

Figure 7 Submitting the job
Click to enlarge

After submitting the job, click Start on the job development page. In the displayed dialog box, set required parameters and click OK.

Figure 8 Starting the job
Click to enlarge

**Table 8** Parameters for starting the job
Parameter	Description
Synchronous Mode	Incremental Synchronization: Incremental data synchronization starts from a specified time point. Full and incremental synchronization: All data is synchronized first, and then incremental data is synchronized in real time.
Time	This parameter must be set for incremental synchronization, and it specifies the start time of incremental synchronization. NOTE: If you set a time that is earlier than the earliest CDC log time, the latest log time is used.

Monitor the job.

On the job development page, click Monitor to go to the Job Monitoring page. You can view the status and log of the job, and configure alarm rules for the job. For details, see Real-Time Migration Job O&M.

Figure 9 Monitoring the job