This topic describes the parameters that are supported by KingbaseES Writer and how to configure KingbaseES Writer by using the codeless user interface (UI) and code editor.

Background information

KingbaseES Writer writes data to tables stored in KingbaseES databases. KingbaseES Writer connects to a remote KingbaseES database by using Java Database Connectivity (JDBC) and executes the INSERT INTO or REPLACE INTO statement to write data to the KingbaseES database. KingbaseES uses the InnoDB engine so that data is written to the database in batches.

KingbaseES Writer can also be used as a data migration tool by users such as database administrators. KingbaseES Writer obtains data from a reader and writes the data to the destination database based on the value of the writeMode parameter.
Note A synchronization node that uses KingbaseES Writer must have at least the permissions to execute the INSERT INTO or REPLACE INTO statement. Whether other permissions are required depends on the SQL statements that you specify in the preSql and postSql parameters when you configure the node.

Parameters

Parameter Description Required Default value
datasource The name of the data source. It must be the same as the name of the added data source. You can add data sources in the code editor. Yes No default value
table The name of the table you want to synchronize. Yes No default value
column The columns in the destination table. Separate the columns with commas (,). Example: "column":["id","name","age"].

To write data to all the columns in the destination table, set the value to an asterisk (*), for example, "column":["*"].

Yes No default value
preSql The SQL statement to execute before the sync node is run. You can execute only one SQL statement on the codeless UI and multiple SQL statements in the code editor. For example, to clear old data from the table before execution:
truncate table tablename
.
Note If you specify multiple SQL statements, they may not be executed in the same transaction.
No No default value
postSql The SQL statement to execute after the sync node is run. You can execute only one SQL statement on the codeless UI and multiple SQL statements in the code editor. For example, you can execute the alter table tablename add colname timestamp DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP statement to add a timestamp after data synchronization. No No default value
batchSize The number of records that can be submitted at a time. You can set this parameter to reduce the frequency of interaction between Data Integration and SAP HANA on the network, and increase the overall throughput. An excessively large value may lead to the out of memory (OOM) error during the data synchronization process. No 1024

Configure KingbaseES Writer by using the codeless UI

  1. Configure data sources.
    Configure Source and Target for the synchronization node. Configure data sources
    Parameter Description
    Data source This parameter corresponds to the datasource parameter that is described in the Parameters section. Select the name of a data source that you have configured.
    Table The table parameter in the preceding parameter description.
    Statement Run Before Writing The preSql parameter in the preceding parameter description. Enter an SQL statement to execute before the sync node is run.
    Statement Run After Writing The postSql parameter in the preceding parameter description. Enter an SQL statement to execute after the sync node is run.
  2. Configure field mapping. It is equivalent to setting the column parameter in the preceding parameter description. Fields in the source table on the left have a one-to-one mapping with fields in the destination table on the right.Field Mapping section
    GUI element Description
    The same name mapping Click The same name mapping to establish a mapping between fields with the same name. Note that the data types of the fields must match.
    Peer mapping Click Peer mapping to establish a mapping between fields in the same row. Note that the data types of the fields must match.
    Unmap Click Unmap to remove mappings that have been established.
    Automatic typesetting Click Automatic typesetting to sort the fields based on specified rules.

Configure KingbaseES Writer by using the code editor

In the following code, a synchronization node is configured to write data to a KingbaseES database:
{
    "type":"job",
    "version":"2.0",// The version number. 
    "steps":[
        {
            "stepType":"stream",
            "parameter":{},
            "name":"Reader",
            "category":"reader"
        },
        {
            "stepType":"kingbasees",// The writer type. 
            "parameter":{
                "postSql":[],// The SQL statement that you want to execute after the synchronization node is run. 
                "datasource":"",// The name of the data source. 
                "column":[// The names of the columns to which you want to write data. 
                    "id",
                    "value"
                ],
                "batchSize":1024,// The number of data records to write at a time. 
                "table":"",// The name of the table to which you want to write data. 
                "preSql":[
                     "delete from XXX;" // The SQL statement that you want to execute before the synchronization node is run. 
                   ]
            },
            "name":"Writer",
            "category":"writer"
        }
    ],
    "setting":{
        "errorLimit":{// The maximum number of dirty data records allowed. 
            "record":"0"
        },
        "speed":{
            "throttle":true,// Specifies whether to enable bandwidth throttling. The value false indicates that bandwidth throttling is disabled, and the value true indicates that bandwidth throttling is enabled. The mbps parameter takes effect only when the throttle parameter is set to true. 
            "concurrent":1, // The maximum number of parallel threads. 
            "mbps":"12"// The maximum transmission rate.
        }
    },
    "order":{
        "hops":[
            {
                "from":"Reader",
                "to":"Writer"
            }
        ]
    }
}