leonardBang commented on a change in pull request #18738: URL: https://github.com/apache/flink/pull/18738#discussion_r806721189
########## File path: docs/content.zh/docs/connectors/table/formats/ogg.md ########## @@ -0,0 +1,256 @@ +--- +title: Ogg +weight: 8 +type: docs +aliases: +- /dev/table/connectors/formats/ogg.html +--- +<!-- +Licensed to the Apache Software Foundation (ASF) under one +or more contributor license agreements. See the NOTICE file +distributed with this work for additional information +regarding copyright ownership. The ASF licenses this file +to you under the Apache License, Version 2.0 (the +"License"); you may not use this file except in compliance +with the License. You may obtain a copy of the License at + + http://www.apache.org/licenses/LICENSE-2.0 + +Unless required by applicable law or agreed to in writing, +software distributed under the License is distributed on an +"AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY +KIND, either express or implied. See the License for the +specific language governing permissions and limitations +under the License. +--> + +# Ogg Format + +{{< label "Changelog-Data-Capture Format" >}} {{< label "Format: Serialization Schema" >}} {{< +label "Format: Deserialization Schema" >}} + +[Oracle GoldenGate](https://www.oracle.com/integration/goldengate//) (a.k.a ogg) 是一个实现异构 IT 环境间数据实时数据集成和复制的综合软件包。 +该产品集支持高可用性解决方案、实时数据集成、事务更改数据捕获、运营和分析企业系统之间的数据复制、转换和验证。Ogg 为变更日志提供了统一的格式结构，并支持使用 JSON 序列化消息。 + +Flink 支持将 Ogg JSON 消息解析为 INSERT/UPDATE/DELETE 消息到 Flink SQL 系统中。在很多情况下，利用这个特性非常有用，例如 + +- 将增量数据从数据库同步到其他系统 +- 日志审计 +- 数据库的实时物化视图 +- 关联维度数据库的变更历史，等等 + +Flink 还支持将 Flink SQL 中的 INSERT/UPDATE/DELETE 消息编码为 Ogg JSON 格式的消息, 输出到 Kafka 等存储中。 +但需要注意, 目前 Flink 还不支持将 UPDATE_BEFORE 和 UPDATE_AFTER 合并为一条 UPDATE 消息. 因此, Flink 将 UPDATE_BEFORE 和 UPDATE_AFTER +分别编码为 DELETE 和 INSERT 类型的 Ogg 消息。 + +Dependencies +------------ + +#### Ogg Json + +{{< sql_download_table "ogg-json" >}} + +*注意: 请参考 [Ogg Kafka Handler documentation](https://docs.oracle.com/en/middleware/goldengate/big-data/19.1/gadbd/using-kafka-handler.html)， +了解如何设置 Ogg Kafka handler 来将变更日志同步到 Kafka 的 Topic。* + + +How to use Ogg format +---------------- + +Ogg 为变更日志提供了统一的格式, 这是一个 JSON 格式的从 Oracle `PRODUCTS` 表捕获的更新操作的简单示例： + +```json +{ + "before": { + "id": 111, + "name": "scooter", + "description": "Big 2-wheel scooter", + "weight": 5.18 + }, + "after": { + "id": 111, + "name": "scooter", + "description": "Big 2-wheel scooter", + "weight": 5.15 + }, + "op_type": "U", + "op_ts": "2020-05-13 15:40:06.000000", + "current_ts": "2020-05-13 15:40:07.000000", + "primary_keys": [ + "id" + ], + "pos": "00000000000000000000143", + "table": "PRODUCTS" +} +``` + +*注意：请参考 [Debezium documentation](https://debezium.io/documentation/reference/1.3/connectors/mysql.html#mysql-connector-events_debezium) +了解每个字段的含义.* + +Oracle `PRODUCTS` 表 有 4 列 (`id`, `name`, `description` and `weight`). 上面的 JSON 消息是 `PRODUCTS` 表上的一条更新事件，其中 `id = 111` 的行的 +`weight` 值从 `5.18` 更改为 `5.15`. 假设此消息已同步到 Kafka 的 Topic `products_ogg`, 则可以使用以下 DDL 来使用该 Topic 并解析更新事件。 + +```sql +CREATE TABLE topic_products ( + -- schema is totally the same to the MySQL "products" table + id BIGINT, + name STRING, + description STRING, + weight DECIMAL(10, 2) +) WITH ( + 'connector' = 'kafka', + 'topic' = 'products_ogg', + 'properties.bootstrap.servers' = 'localhost:9092', + 'properties.group.id' = 'testGroup', + 'format' = 'ogg-json' +) +``` + +再将 Kafka Topic 注册为 Flink 表之后， 可以将 OGG 消息变为变更日志源。 + +```sql +-- a real-time materialized view on the Oracle "PRODUCTS" +-- which calculate the latest average of weight for the same products +SELECT name, AVG(weight) +FROM topic_products +GROUP BY name; + +-- synchronize all the data and incremental changes of Oracle "PRODUCTS" table to +-- Elasticsearch "products" index for future searching +INSERT INTO elasticsearch_products +SELECT * +FROM topic_products; +``` + +Available Metadata +------------------ + +The following format metadata can be exposed as read-only (`VIRTUAL`) columns in a table definition. + +<span class="label label-danger">Attention</span> Format metadata fields are only available if the +corresponding connector forwards format metadata. Currently, only the Kafka connector is able to +expose metadata fields for its value format. + +<table class="table table-bordered"> + <thead> + <tr> + <th class="text-left" style="width: 25%">Key</th> + <th class="text-center" style="width: 40%">Data Type</th> + <th class="text-center" style="width: 40%">Description</th> + </tr> + </thead> + <tbody> + <tr> + <td><code>table</code></td> + <td><code>STRING NULL </code></td> + <td>Contains fully qualified table name. The format of the fully qualified table name is: + CATALOG NAME.SCHEMA NAME.TABLE NAME</td> + </tr> + <tr> + <td><code>primary_keys</code></td> + <td><code>ARRAY<STRING> NULL</code></td> + <td>An array variable holding the column names of the primary keys of the source table. + The primary_keys field is only include in the JSON output if the includePrimaryKeys + configuration property is set to true.</td> + </tr> + <tr> + <td><code>ingestion-timestamp</code></td> + <td><code>TIMESTAMP_LTZ(6) NULL</code></td> + <td>The timestamp at which the connector processed the event. Corresponds to the current_ts field in the Ogg record.</td> + </tr> + <tr> + <td><code>event-timestamp</code></td> + <td><code>TIMESTAMP_LTZ(6) NULL</code></td> + <td>The timestamp at which the source system created the event. Corresponds to the op_ts field in the Ogg record.</td> + </tr> + </tbody> +</table> + +The following example shows how to access Ogg metadata fields in Kafka: + +```sql +CREATE TABLE KafkaTable ( + origin_ts TIMESTAMP(3) METADATA FROM 'value.ingestion-timestamp' VIRTUAL, + event_time TIMESTAMP(3) METADATA FROM 'value.event-timestamp' VIRTUAL, + origin_table STRING METADATA FROM 'value.table' VIRTUAL, + primary_keys ARRAY<STRING> METADATA FROM 'value.primary_keys' VIRTUAL, Review comment: primary-keys -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: [email protected] For queries about this service, please contact Infrastructure at: [email protected]
