fix: query timeout kill query directed to incorrect instance

[crystall-bitquill]

Summary

fix: query timeout kill query directed to incorrect instance

Description

When a query timeout is set and the timeout value has passed, the driver sends a kill query to stop the process through a new connection that was created using the same host as the original connection. When using the reader cluster url, connections are randomly sent to one of the available reader instances. This will occasionally cause errors when the kill query is sent to a different instance where the statement was not executed, resulting in an "Unknown process id" message.

This PR adds a check in the default connection plugin for connections using the reader cluster url. Once the connection is made using the reader cluster url, a new connection is made to a reader instance that is obtained by querying for the current instance name. The original connection using the reader cluster is replaced with the connection to the instance.

Addresses #461

Additional Reviewers

[sergiyvamz]

Why do we need to run it so many times?

[crystall-bitquill]

When the new connection for the query timeout is made, the reader cluster endpoint doesn't always choose a reader different from the original connection so it's hard to reproduce this issue consistently.

[sergiyvamz]

I'd suggest to relocate this logic into a new plugin. In this way, it'd be easier for users to use it when it's needed, or skip it. That gives more flexibility for users who don't experience any issue with query timeout.

[sergiyvamz]

com.mysql.cj.jdbc.ha.util ?

[sergiyvamz]

And similar suggestion's for the ConnectionUtils class above.

[karenc-bq]

I don't think logger is used in this file. Do we need to store it?

[karenc-bq]

Suggested change

	String instanceEndpoint =
	rdsUtils.getRdsInstanceHostPattern(mainHostInfo.getHost()).replace("?", connectedHostName);
	if (!StringUtils.isNullOrEmpty(
	mainHostInfo.getHostProperties().get(PropertyKey.clusterInstanceHostPattern.getKeyName()))) {
	instanceEndpoint = mainHostInfo.getHostProperties().get(PropertyKey.clusterInstanceHostPattern.getKeyName())
	.replace("?", connectedHostName);
	}
	final HostInfo instanceHostInfo =
	ConnectionUtils.createInstanceHostWithProperties(instanceEndpoint, mainHostInfo);
	final String pattern = mainHostInfo.getHostProperties().get(PropertyKey.clusterInstanceHostPattern.getKeyName());
	final String instanceEndpoint = !StringUtils.isNullOrEmpty(pattern) ? pattern : rdsUtils.getRdsInstanceHostPattern(mainHostInfo.getHost());
	final HostInfo instanceHostInfo =
	ConnectionUtils.createInstanceHostWithProperties(
	instanceEndpoint.replace("?", connectedHostName),
	mainHostInfo);

[karenc-bq]

Suggested change

	rs.next();
	return rs.getString(1);
	if (rs.next()) {
	return rs.getString(1);
	}
	return null;
	}