Apache Paimon 使用 MySQL CDC 获取数据

Paimon支持使用（CDC）同步来自不同数据库的更改，此功能需要Flink及其CDC连接器。

准备 CDC Bundled Jar 依赖

flink-sql-connector-mysql-cdc-*.jar

同步表

在Flink DataStream中或通过flink run使用MySqlSyncTableAction，可以将MySQL中的一个或多个表同步到一个Paimon表中。

<FLINK_HOME>/bin/flink run \
    /path/to/paimon-flink-action-0.7.0-incubating.jar \
    mysql_sync_table
    --warehouse <warehouse-path> \
    --database <database-name> \
    --table <table-name> \
    [--partition_keys <partition_keys>] \
    [--primary_keys <primary-keys>] \
    [--type_mapping <option1,option2...>] \
    [--computed_column <'column-name=expr-name(args[, ...])'> [--computed_column ...]] \
    [--metadata_column <metadata-column>] \
    [--mysql_conf <mysql-cdc-source-conf> [--mysql_conf <mysql-cdc-source-conf> ...]] \
    [--catalog_conf <paimon-catalog-conf> [--catalog_conf <paimon-catalog-conf> ...]] \
    [--table_conf <paimon-table-sink-conf> [--table_conf <paimon-table-sink-conf> ...]]

Configuration	Description
--warehouse	The path to Paimon warehouse.
--database	The database name in Paimon catalog.
--table	The Paimon table name.
--partition_keys	The partition keys for Paimon table. If there are multiple partition keys, connect them with comma, for example "dt,hh,mm".
--primary_keys	The primary keys for Paimon table. If there are multiple primary keys, connect them with comma, for example "buyer_id,seller_id".
--type_mapping	It is used to specify how to map MySQL data type to Paimon type. Supported options:"tinyint1-not-bool": maps MySQL TINYINT(1) to TINYINT instead of BOOLEAN."to-nullable": ignores all NOT NULL constraints (except for primary keys). This is used to solve the problem that Flink cannot accept the MySQL 'ALTER TABLE ADD COLUMN column type NOT NULL DEFAULT x' operation."to-string": maps all MySQL types to STRING."char-to-string": maps MySQL CHAR(length)/VARCHAR(length) types to STRING."longtext-to-bytes": maps MySQL LONGTEXT types to BYTES."bigint-unsigned-to-bigint": maps MySQL BIGINT UNSIGNED, BIGINT UNSIGNED ZEROFILL, SERIAL to BIGINT. You should ensure overflow won't occur when using this option.
--computed_column	The definitions of computed columns. The argument field is from MySQL table field name. See here for a complete list of configurations.
--metadata_column	--metadata_column is used to specify which metadata columns to include in the output schema of the connector. Metadata columns provide additional information related to the source data, for example: --metadata_column table_name,database_name,op_ts. See its document for a complete list of available metadata.
--mysql_conf	The configuration for Flink CDC MySQL sources. Each configuration should be specified in the format "key=value". hostname, username, password, database-name and table-name are required configurations, others are optional. See its document for a complete list of configurations.
--catalog_conf	The configuration for Paimon catalog. Each configuration should be specified in the format "key=value". See here for a complete list of catalog configurations.
--table_conf	The configuration for Paimon table sink. Each configuration should be specified in the format "key=value". See here for a complete list of table configurations.

如果指定的Paimon表不存在，将自动创建该表。它的模式将从所有指定的MySQL表中派生出来。如果Paimon表已经存在，其模式将与所有指定MySQL表的模式进行比较。

示例1：将表同步到一个Paimon表中

<FLINK_HOME>/bin/flink run \
    /path/to/paimon-flink-action-0.7.0-incubating.jar \
    mysql_sync_table \
    --warehouse hdfs:///path/to/warehouse \
    --database test_db \
    --table test_table \
    --partition_keys pt \
    --primary_keys pt,uid \
    --computed_column '_year=year(age)' \
    --mysql_conf hostname=127.0.0.1 \
    --mysql_conf username=root \
    --mysql_conf password=123456 \
    --mysql_conf database-name='source_db' \
    --mysql_conf table-name='source_table1|source_table2' \
    --catalog_conf metastore=hive \
    --catalog_conf uri=thrift://hive-metastore:9083 \
    --table_conf bucket=4 \
    --table_conf changelog-producer=input \
    --table_conf sink.parallelism=4

如上示例所示，mysql_conf的表名支持正则表达式，以监控满足正则表达式的多个表。所有表的模式将合并到一个Paimon表模式中。

示例2：将分片同步到一个Paimon表中

可以使用正则表达式设置"数据库名称"来捕获多个数据库。典型的场景是，表"source_table"被拆分为数据库"source_db1"，"source_db2"...，然后将所有"source_table"的数据同步到一个Paimon表中。

<FLINK_HOME>/bin/flink run \
    /path/to/paimon-flink-action-0.7.0-incubating.jar \
    mysql_sync_table \
    --warehouse hdfs:///path/to/warehouse \
    --database test_db \
    --table test_table \
    --partition_keys pt \
    --primary_keys pt,uid \
    --computed_column '_year=year(age)' \
    --mysql_conf hostname=127.0.0.1 \
    --mysql_conf username=root \
    --mysql_conf password=123456 \
    --mysql_conf database-name='source_db.+' \
    --mysql_conf table-name='source_table' \
    --catalog_conf metastore=hive \
    --catalog_conf uri=thrift://hive-metastore:9083 \
    --table_conf bucket=4 \
    --table_conf changelog-producer=input \
    --table_conf sink.parallelism=4

同步数据库

通过在Flink DataStream或通过flink run使用MySqlSyncDatabaseAction，可以将整个MySQL数据库同步到一个Paimon数据库中。

<FLINK_HOME>/bin/flink run \
    /path/to/paimon-flink-action-0.7.0-incubating.jar \
    mysql_sync_database
    --warehouse <warehouse-path> \
    --database <database-name> \
    [--ignore_incompatible <true/false>] \
    [--merge_shards <true/false>] \
    [--table_prefix <paimon-table-prefix>] \
    [--table_suffix <paimon-table-suffix>] \
    [--including_tables <mysql-table-name|name-regular-expr>] \
    [--excluding_tables <mysql-table-name|name-regular-expr>] \
    [--mode <sync-mode>] \
    [--metadata_column <metadata-column>] \
    [--type_mapping <option1,option2...>] \
    [--mysql_conf <mysql-cdc-source-conf> [--mysql_conf <mysql-cdc-source-conf> ...]] \
    [--catalog_conf <paimon-catalog-conf> [--catalog_conf <paimon-catalog-conf> ...]] \
    [--table_conf <paimon-table-sink-conf> [--table_conf <paimon-table-sink-conf> ...]]

Configuration	Description
--warehouse	The path to Paimon warehouse.
--database	The database name in Paimon catalog.
--ignore_incompatible	It is default false, in this case, if MySQL table name exists in Paimon and their schema is incompatible,an exception will be thrown. You can specify it to true explicitly to ignore the incompatible tables and exception.
--merge_shards	It is default true, in this case, if some tables in different databases have the same name, their schemas will be merged and their records will be synchronized into one Paimon table. Otherwise, each table's records will be synchronized to a corresponding Paimon table, and the Paimon table will be named to 'databaseName_tableName' to avoid potential name conflict.
--table_prefix	The prefix of all Paimon tables to be synchronized. For example, if you want all synchronized tables to have "ods_" as prefix, you can specify "--table_prefix ods_".
--table_suffix	The suffix of all Paimon tables to be synchronized. The usage is same as "--table_prefix".
--including_tables	It is used to specify which source tables are to be synchronized. You must use '|' to separate multiple tables.Because '|' is a special character, a comma is required, for example: 'a|b|c'.Regular expression is supported, for example, specifying "--including_tables test|paimon.*" means to synchronize table 'test' and all tables start with 'paimon'.
--excluding_tables	It is used to specify which source tables are not to be synchronized. The usage is same as "--including_tables". "--excluding_tables" has higher priority than "--including_tables" if you specified both.
--mode	It is used to specify synchronization mode. Possible values:"divided" (the default mode if you haven't specified one): start a sink for each table, the synchronization of the new table requires restarting the job."combined": start a single combined sink for all tables, the new table will be automatically synchronized.
--metadata_column	--metadata_column is used to specify which metadata columns to include in the output schema of the connector. Metadata columns provide additional information related to the source data, for example: --metadata_column table_name,database_name,op_ts. See its document for a complete list of available metadata.
--type_mapping	It is used to specify how to map MySQL data type to Paimon type. Supported options:"tinyint1-not-bool": maps MySQL TINYINT(1) to TINYINT instead of BOOLEAN."to-nullable": ignores all NOT NULL constraints (except for primary keys). This is used to solve the problem that Flink cannot accept the MySQL 'ALTER TABLE ADD COLUMN column type NOT NULL DEFAULT x' operation."to-string": maps all MySQL types to STRING."char-to-string": maps MySQL CHAR(length)/VARCHAR(length) types to STRING."longtext-to-bytes": maps MySQL LONGTEXT types to BYTES."bigint-unsigned-to-bigint": maps MySQL BIGINT UNSIGNED, BIGINT UNSIGNED ZEROFILL, SERIAL to BIGINT. You should ensure overflow won't occur when using this option.
--mysql_conf	The configuration for Flink CDC MySQL sources. Each configuration should be specified in the format "key=value". hostname, username, password, database-name and table-name are required configurations, others are optional. See its document for a complete list of configurations.
--catalog_conf	The configuration for Paimon catalog. Each configuration should be specified in the format "key=value". See here for a complete list of catalog configurations.
--table_conf	The configuration for Paimon table sink. Each configuration should be specified in the format "key=value". See here for a complete list of table configurations.

只有带有主键的表才会同步。

对于要同步的每个MySQL表，如果相应的Paimon表不存在，将自动创建该表。它的模式将从所有指定的MySQL表中派生出来。如果Paimon表已经存在，其模式将与所有指定MySQL表的模式进行比较。

示例1：同步整个数据库

<FLINK_HOME>/bin/flink run \
    /path/to/paimon-flink-action-0.7.0-incubating.jar \
    mysql_sync_database \
    --warehouse hdfs:///path/to/warehouse \
    --database test_db \
    --mysql_conf hostname=127.0.0.1 \
    --mysql_conf username=root \
    --mysql_conf password=123456 \
    --mysql_conf database-name=source_db \
    --catalog_conf metastore=hive \
    --catalog_conf uri=thrift://hive-metastore:9083 \
    --table_conf bucket=4 \
    --table_conf changelog-producer=input \
    --table_conf sink.parallelism=4

示例2：同步数据库下新添加的表

首先，假设Flink作业是在数据库source_db下同步表产品、用户、地址。

<FLINK_HOME>/bin/flink run \
    /path/to/paimon-flink-action-0.7.0-incubating.jar \
    mysql_sync_database \
    --warehouse hdfs:///path/to/warehouse \
    --database test_db \
    --mysql_conf hostname=127.0.0.1 \
    --mysql_conf username=root \
    --mysql_conf password=123456 \
    --mysql_conf database-name=source_db \
    --catalog_conf metastore=hive \
    --catalog_conf uri=thrift://hive-metastore:9083 \
    --table_conf bucket=4 \
    --table_conf changelog-producer=input \
    --table_conf sink.parallelism=4 \
    --including_tables 'product|user|address'

然后，希望该Job也同步包含历史数据的表order, custom。可以通过从之前的Job快照中恢复，从而重用作业的现有状态来实现这一点。恢复的Job将首先快照新添加的表，然后自动从上一个位置继续读取changelog。

从以前的快照恢复并添加新表进行同步的命令如下所示：

<FLINK_HOME>/bin/flink run \
    --fromSavepoint savepointPath \
    /path/to/paimon-flink-action-0.7.0-incubating.jar \
    mysql_sync_database \
    --warehouse hdfs:///path/to/warehouse \
    --database test_db \
    --mysql_conf hostname=127.0.0.1 \
    --mysql_conf username=root \
    --mysql_conf password=123456 \
    --mysql_conf database-name=source_db \
    --catalog_conf metastore=hive \
    --catalog_conf uri=thrift://hive-metastore:9083 \
    --table_conf bucket=4 \
    --including_tables 'product|user|address|order|custom'

注意：可以设置--mode combined启动，自动不同新增加的表而无需重启Job。

示例3：同步和合并多个碎片

假设有多个数据库分片db1，db2，...每个数据库都有表tbl1，tbl2，...，可以同步所有的db.+.tbl.+到表test_db.tbl1, test_db.tbl2 ...。

<FLINK_HOME>/bin/flink run \
    /path/to/paimon-flink-action-0.7.0-incubating.jar \
    mysql_sync_database \
    --warehouse hdfs:///path/to/warehouse \
    --database test_db \
    --mysql_conf hostname=127.0.0.1 \
    --mysql_conf username=root \
    --mysql_conf password=123456 \
    --mysql_conf database-name='db.+' \
    --catalog_conf metastore=hive \
    --catalog_conf uri=thrift://hive-metastore:9083 \
    --table_conf bucket=4 \
    --table_conf changelog-producer=input \
    --table_conf sink.parallelism=4 \
    --including_tables 'tbl.+'

通过将数据库名称设置为正则表达式，同步作业将捕获匹配数据库下的所有表，并将同名的表合并到一个表中。

设置--merge_shards false，以防止合并分片。同步表将被命名为"databaseName_tableName"，以避免潜在的名称冲突。

常见问题

1. 从MySQL中提取的数据汉字乱码

• 在flink-conf.yaml设置env.java.opts: -Dfile.encoding=UTF-8（自Flink-1.17以来，该选项已更改为env.java.opts.all）。