CDC Polling mode get errors when source database restart

[luongdq]

Description:

A Siddhi app with CDC polling mode get following errors when the source database restart.
These failures caused by the bug in DefaultPollingStrategy class, printEvent(connection) do not verify connection before using it.

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[2020-11-17 18:48:50,328] ERROR {io.siddhi.extension.io.cdc.source.polling.strategies.DefaultPollingStrategy} - Error occurred while processing records in table SweetProductionTable. {mode=polling, app=CDCWithPollingMode, stream=insertSweetProductionStream} java.sql.SQLException: Connection is closed
at com.zaxxer.hikari.pool.ProxyConnection$ClosedConnection.lambda$getClosedConnection$0(ProxyConnection.java:493)
at com.sun.proxy.$Proxy73.prepareStatement(Unknown Source)
at com.zaxxer.hikari.pool.ProxyConnection.prepareStatement(ProxyConnection.java:315)
at com.zaxxer.hikari.pool.HikariProxyConnection.prepareStatement(HikariProxyConnection.java)
at io.siddhi.extension.io.cdc.source.polling.strategies.DefaultPollingStrategy.printEvent(DefaultPollingStrategy.java:142)
at io.siddhi.extension.io.cdc.source.polling.strategies.DefaultPollingStrategy.poll(DefaultPollingStrategy.java:86)
at io.siddhi.extension.io.cdc.source.polling.CDCPoller.run(CDCPoller.java:202)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
at java.lang.Thread.run(Thread.java:748)

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Suggested Labels:

bug
Suggested Assignees:

Affected Product Version:
2.0.6
OS, DB, other environment details and versions:

Steps to reproduce:

Related Issues:

[luongdq]

This issue is fixed by adding isClosed() to check if db connection valid and get new connection if need. I've updated DefaultPollingStrategy.java