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https://issues.apache.org/jira/browse/FLINK-20657?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17252450#comment-17252450
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Kezhu Wang commented on FLINK-20657:
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I see {{SimpleJdbcConnectionProvider}} has been shaped as some kind of
container of established connection, so I propose to add
{{SimpleJdbcConnectionProvider.closeConnection}} otherwise it is not possible
to clear {{SimpleJdbcConnectionProvider.connection}}. Another direction is
providing factory-like method
{{SimpleJdbcConnectionProvider.createConnection}}. {{PostgresCatalog}} may need
this as it has multiple ephemeral connections for different databases if it
take {{driverName}} into account and migrate to
{{SimpleJdbcConnectionProvider}} finally. In that stage,
{{JdbcConnectionProvider}} could extend an new interface
{{JdbConnectionFactory}} to provide that functionality.
Besides this, is there any reason why we need {{synchronized(this)}} in
{{SimpleJdbcConnectionProvider.getConnection}} ? Should we drop it ?
[~roman_khachatryan] [~jark] What do you think ? Could you mind assign this to
me if above sounds good to you ?
> Migrate jdbc connection code of JdbcInputFormat, JdbcLookupFunction,
> JdbcRowDataLookupFunction to SimpleJdbcConnectionProvider
> ------------------------------------------------------------------------------------------------------------------------------
>
> Key: FLINK-20657
> URL: https://issues.apache.org/jira/browse/FLINK-20657
> Project: Flink
> Issue Type: Improvement
> Components: Connectors / JDBC, Table SQL / Ecosystem
> Affects Versions: 1.13.0
> Reporter: Kezhu Wang
> Priority: Major
>
> Currently, there are multiple places to establish jdbc connection, several of
> them were written before introducing of {{JdbcConnectionProvider}} in
> FLINK-15782. We need to migrate these classes for reasons:
> * Code reusability.
> * Circumvent pitfalls of {{DriverManager}} such as FLINK-19435 and possible
> [others|https://ci.apache.org/projects/tomcat/tomcat85/docs/jndi-datasource-examples-howto.html#DriverManager,_the_service_provider_mechanism_and_memory_leaks]
> in one place.
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