#147: Refactor to open and close connection for each query

[mrjameshamilton]

Fix #147 by opening and closing connections for each query.

[jakelandis]

@mrjameshamilton - thanks for the PR and I agree with the changes here.

It is worth noting that if some workflows may require highly frequent schedules (e.g. every 1 second) with large numbers of connections which may cause resource issues w/r/t to number of sockets in TIME_WAIT status. However, I think that is the exception not the rule, and the fix for that exception case is connection pooling, not the current behavior.

I did some light testing against mysql shows the connections correctly being open/closed as advertised.

LGTM, I will get this merged and released.

[elasticsearch-bot]

Jake Landis merged this into the following branches!

Branch	Commits
master	733abd9

[jakelandis]

This has been released:

bin/logstash-plugin install --version "4.3.0" logstash-input-jdbc

Thanks again @mrjameshamilton !