Improve performance with else if

[widhalmt]

The current filters have a lot of if checks. But when we look closely we see that most events can only match one filter in a file and not many. So after the first match we can skip testing for more hits. This skipping can be achieved by changing if into else if.

So check all filter files and replace if with else if where appropriate.

[widhalmt]

Hint: Filter for a single component, View as big a timeframe as possible and have Kibana show you which messages are the most common (there's a postfix.event_type field for that). Then sort all filters so that the most used are on top. Do this before changing to else if and you'll end up with an optimised file.

[widhalmt]

But keep in mind that not all Postfix setups are alike and you can only tune for one kind. So don't overdo it.