使用Debezium和Kafka Connect JDBC接收器连接器同步数据库时，如何重命名主键？

如何解决使用Debezium和Kafka Connect JDBC接收器连接器同步数据库时，如何重命名主键？

我试图按照Debezium博客here中描述的方法，使用Debezium将上游数据库中的表同步到下游数据库。

在下游表中，我只需要上游表中的某些列。我还希望更改某些列名称（包括主键的名称）。 如果我不尝试重命名主键，则同步将正常进行。

我正在使用：

适用于两个数据库的
• SQL Server 2019;和
• Debezium 1.3（但也尝试过与Debezium 1.2取得相同的结果）。

我在下面列出了我的数据库和连接器设置的全部详细信息。

（1）数据库表定义：

上游表的DDL为：

CREATE TABLE [kafkatest.service1].dbo.Users (
    Id int IDENTITY(1,1) NOT NULL,Name nvarchar COLLATE SQL_Latin1_General_CP1_CI_AS NULL,CONSTRAINT PK_Users PRIMARY KEY (Id)
) GO

下游表的DDL为：

CREATE TABLE [kafkatest.service2].dbo.Users (
    LocalId int IDENTITY(1,// added to avoid IDENTITY_INSERT issue with SQL Server
    ExternalId int NOT NULL,ExternalName nvarchar COLLATE SQL_Latin1_General_CP1_CI_AS NULL,CONSTRAINT PK_Users PRIMARY KEY (LocalId)
) GO

尤其要注意，上游表中的'Id'列（这是主键）应映射到'ExternalId'下游表中的/ strong>列。

（2）Kafka Connect连接器定义：

源连接器：

{
    "name": "users-connector","config": {
    "connector.class": "io.debezium.connector.sqlserver.SqlServerConnector","tasks.max": "1","database.server.name": "sqlserver","database.hostname": "sqlserver","database.port": "1433","database.user": "sa","database.password": "Password!","database.dbname": "kafkatest.service1","database.history.kafka.bootstrap.servers": "kafka:9092","database.history.kafka.topic": "schema-changes.users","table.whitelist": "dbo.Users"
  }
}

水槽连接器：

{
    "name": "jdbc-sink","config": {
        "connector.class": "io.confluent.connect.jdbc.JdbcSinkConnector","topics.regex": "sqlserver\\.dbo\\.(Users)","connection.url": "jdbc:sqlserver://sqlserver:1433;databaseName=kafkatest.service2","connection.user": "sa","connection.password": "Password!","transforms": "unwrap,route,RenameField","transforms.unwrap.type": "io.debezium.transforms.ExtractNewRecordState","transforms.unwrap.drop.tombstones": "false","transforms.route.type": "org.apache.kafka.connect.transforms.RegexRouter","transforms.route.regex": "(?:[^.]+)\\.(?:[^.]+)\\.([^.]+)","transforms.route.replacement": "$1","transforms.RenameField.type": "org.apache.kafka.connect.transforms.ReplaceField$Value","transforms.RenameField.renames": "Id:ExternalId,Name:ExternalName","auto.create": "false","auto.evolve": "false","insert.mode": "upsert","delete.enabled": "true","pk.fields": "Id","pk.mode": "record_key"
    }
}

据我所知，“ pk.mode”必须为“ record_key”才能启用删除。我尝试将“ pk.fields”值设置为“ Id”和“ ExternalId”，但均无效。

（3）错误消息：

在第一种情况下（即“ pk.fields”：“ Id”），出现以下错误：

2020-08-18 10:16:16,951 INFO   ||  Unable to find fields [SinkRecordField{schema=Schema{INT32},name='Id',isPrimaryKey=true}] among column names [ExternalId,ExternalName,LocalId]   [io.confluent.connect.jdbc.sink.DbStructure]
2020-08-18 10:16:16,952 ERROR  ||  WorkerSinkTask{id=jdbc-sink-0} Task threw an uncaught and unrecoverable exception. Task is being killed and will not recover until manually restarted. Error: Cannot ALTER TABLE "Users" to add missing field SinkRecordField{schema=Schema{INT32},isPrimaryKey=true},as the field is not optional and does not have a default value   [org.apache.kafka.connect.runtime.WorkerSinkTask]
org.apache.kafka.connect.errors.ConnectException: Cannot ALTER TABLE "Users" to add missing field SinkRecordField{schema=Schema{INT32},as the field is not optional and does not have a default value

在第二种情况下（即“ pk.fields”：“ ExternalId”），出现以下错误：

2020-08-18 10:17:50,192 ERROR  ||  WorkerSinkTask{id=jdbc-sink-0} Task threw an uncaught and unrecoverable exception. Task is being killed and will not recover until manually restarted. Error: PK mode for table 'Users' is RECORD_KEY with configured PK fields [ExternalId],but record key schema does not contain field: ExternalId   [org.apache.kafka.connect.runtime.WorkerSinkTask]
org.apache.kafka.connect.errors.ConnectException: PK mode for table 'Users' is RECORD_KEY with configured PK fields [ExternalId],but record key schema does not contain field: ExternalId

使用Debezium时是否可以重命名主键？还是我总是需要对数据库表进行结构设计，以使上游和下游数据库中的主键名称都匹配？

解决方法

尝试重命名关键字段：

"transforms": "unwrap,route,RenameField,RenameKey",...
"transforms.RenameKey.type": "org.apache.kafka.connect.transforms.ReplaceField$Key","transforms.RenameKey.renames": "Id:ExternalId",

使用"pk.mode": "record_key"时，主键from the message key用于build the upsert query statement。