@lmzhizhe The index template also need to change the data type. [Template API](https://www.elastic.co/guide/en/elasticsearch/reference/6.3/indices-templates.html)

[lmzhizhe]

Can I delete all index template? The template will be created again when I restart the skywalking?

Originally posted by @peng-yongsheng in #3328 (comment)

[wu-sheng]

Don't open a new issue for an existing one. You could delete all indexes and templates, also reboot the agents.

[lmzhizhe]

Don't open a new issue for an existing one. You could delete all indexes and templates, also reboot the agents.
what will happen If I only delete all the templates and do not reboot the agents? I can not reboot all agent。I just can reboot the oap !