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Re: Confusions About JDBCOutputFormat


Hi wangsan,

I agree with you. It would be kind of you to open a jira to check the
problem.

For the first problem, I think we need to establish connection each time
execute batch write. And, it is better to get the connection from a
connection pool.
For the second problem, to avoid multithread problem, I think we should
synchronized the batch object in flush() method.

What do you think?

Best, Hequn



On Tue, Jul 10, 2018 at 2:36 PM, wangsan <wamgsam@xxxxxxx> wrote:

> Hi all,
>
> I'm going to use JDBCAppendTableSink and JDBCOutputFormat in my Flink
> application. But I am confused with the implementation of JDBCOutputFormat.
>
> 1. The Connection was established when JDBCOutputFormat is opened, and
> will be used all the time. But if this connction lies idle for a long time,
> the database will force close the connetion, thus errors may occur.
> 2. The flush() method is called when batchCount exceeds the threshold, but
> it is also called while snapshotting state. So two threads may modify
> upload and batchCount, but without synchronization.
>
> Please correct me if I am wrong.
>
> ——
> wangsan
>