openinx commented on a change in pull request #3085: URL: https://github.com/apache/iceberg/pull/3085#discussion_r711543543
########## File path: site/docs/flink-connector.md ########## @@ -0,0 +1,138 @@ +<!-- + - 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. + --> + +Apache Iceberg supports creating flink table directly without creating the explicit flink catalog in flink SQL in [#2666](https://github.com/apache/iceberg/pull/2666). That means we can just create an iceberg table by specifying `'connector'='iceberg'` table option in flink SQL which is similar to usage in the flink official [document](https://nightlies.apache.org/flink/flink-docs-release-1.13/docs/connectors/table/overview/). + +In flink, the SQL `CREATE TABLE test (..) WITH ('connector'='iceberg', ...)` will create an flink table in current flink catalog (use [GenericInMemoryCatalog](https://ci.apache.org/projects/flink/flink-docs-release-1.13/docs/dev/table/catalogs/#genericinmemorycatalog) by default), +which is just mapping to the underlying iceberg table instead of maintaining iceberg table directly in current flink catalog. + +To create the table in flink SQL by using SQL syntax `CREATE TABLE test (..) WITH ('connector'='iceberg', ...)`, flink iceberg connector provides the following table properties: + +* `connector`: Use the constant `iceberg`. +* `catalog-name`: User-specified catalog name. It's required because the connector don't have any default value. +* `catalog-type`: Default to use `hive` if don't specify any value. The optional values are: + * `hive`: The hive metastore catalog. + * `hadoop`: The hadoop catalog. + * `custom`: The customized catalog, see [custom catalog](./custom-catalog.md) for more details. +* `catalog-database`: The iceberg database name in the backend catalog, use the current flink database name by default. +* `catalog-table`: The iceberg table name in the backend catalog. Default to use the table name in the flink `CREATE TABLE` sentence. + +## Table managed in hive catalog. + +Before executing the following SQL, please make sure you've configured the flink SQL client correctly according to the quick start [document](./flink.md). + +The following SQL will create an flink table in the current flink catalog, which maps to the iceberg table `default_database.iceberg_table` managed in iceberg catalog. + +```sql +CREATE TABLE flink_table ( + id BIGINT, + data STRING +) WITH ( + 'connector'='iceberg', + 'catalog-name'='hive_prod', + 'uri'='thrift://localhost:9083', + 'warehouse'='hdfs://nn:8020/path/to/warehouse' +); +``` + +If you want to create a flink table mapping to a different iceberg table managed in hive catalog (such as `hive_db.hive_iceberg_table` in hive), then you can create flink table as following: + +```sql +CREATE TABLE flink_table ( + id BIGINT, + data STRING +) WITH ( + 'connector'='iceberg', + 'catalog-name'='hive_prod', + 'catalog-database'='hive_db', + 'catalog-table'='hive_iceberg_table', + 'uri'='thrift://localhost:9083', + 'warehouse'='hdfs://nn:8020/path/to/warehouse' +); +``` + +!!! Note + The underlying catalog database (`hive_db` in the above example) will be created automatically if it does not exist when writing records into the flink table. Review comment: Yes, that's the correct behavior. Because the `CREATE TABLE test (..) WITH ('connector'='iceberg', ...)` is actually creating a table in in-memory catalog by default and it won't do any real thing in the underlying fs. The database & table will be created only when the records are planing to write to table. -- 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] --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
