LLD filter modification doesn't affect exititng items

[mbrackeva]

Zabbix server 3.0.4 on RedHat 7, with MySQL 5.6.

I have made some changes to existing LLD items, more specifically to the filters. I changed a regular expression that was used by a LLD definition. And for another LLD item I removed the filter and added a new one.

When adding the template to a new host it does exactly what I want, so no problems there. But the filter isn't applied to the items that were already discovered. I expected that the filter would kick in at the next discovery interval and remove the filtered items or at least stop collecting data for them. But there seems to be no change at all.

I tried with removing the template from an existing node and adding it again. In that case the filter does its job. But obviously I lost all historical data for that host. ANd I really don't want that.

Is this a bug? Or is this by design? Or have I missed something entirely. As far as I can see the documentation is silent about modifying regular expressions.

[mbrackeva]

Allright, I did miss something entirely.

The reason the items remain is because of the setting "Keep lost resources..." in the LLD definition. After I changed that to 0, and the update interval to 60s, a minute later the filtered items were indeed gone. I changed the value back to 7, otherwise I could loose all history when making a wrong change to a filter.

So, that explains why the items remained in the database. Still weird that the server keeps on polling an undiscovered item.