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https://issues.apache.org/jira/browse/FLINK-9794?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16540045#comment-16540045
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ASF GitHub Bot commented on FLINK-9794:
---------------------------------------
Github user sihuazhou commented on a diff in the pull request:
https://github.com/apache/flink/pull/6301#discussion_r201676322
--- Diff:
flink-connectors/flink-jdbc/src/main/java/org/apache/flink/api/java/io/jdbc/JDBCOutputFormat.java
---
@@ -111,110 +134,117 @@ public void writeRecord(Row row) throws IOException
{
if (typesArray != null && typesArray.length > 0 &&
typesArray.length != row.getArity()) {
LOG.warn("Column SQL types array doesn't match arity of
passed Row! Check the passed array...");
}
- try {
+ synchronized (this) {
--- End diff --
Why do we need synchronized this?
> JDBCOutputFormat does not consider idle connection and multithreads
> synchronization
> -----------------------------------------------------------------------------------
>
> Key: FLINK-9794
> URL: https://issues.apache.org/jira/browse/FLINK-9794
> Project: Flink
> Issue Type: Bug
> Components: Streaming Connectors
> Affects Versions: 1.4.0, 1.5.0
> Reporter: wangsan
> Priority: Major
> Labels: pull-request-available
>
> Current implementation of JDBCOutputFormat has two potential problems:
> 1. The Connection was established when JDBCOutputFormat is opened, and will
> be used all the time. But if this connection lies idle for a long time, the
> database will force close the connection, 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.
> We need fix these two problems to make JDBCOutputFormat more reliable.
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