[Question] No field could be selected when try to sum an aggregation in the visualization

Hi I'm new to Kibana. I follow the guidance and try to visualize a search, but meet some little problems.
I got items like this:

I want to sum the "pos" section of all the items that have the same timestamp, however when I try to visualize, the web shows like this:

Nothing could be selected in the "Field" pull-down menu. What's my mistake?

Hi,

In order to perform the aggregation, the 'pos' field need to be mapped as a number. Go to the Discover mode and verify that this field is indeed mapped as a number (indicated by a '#' in front of the field) and not a string.

Christian

Thanks for reply.
I've checked the value type of the field, it appears to be two fields with 'long' type: the 'pos' and 'neg' field:

But when I used the Discover mode to list the items, there aren't any '#' in front of the field, just as the first picture I posted.

That is odd. Are you querying against a single index in Kibana or using a pattern to query against a set of indices? If you are using a pattern, is the 'pos' and 'neg' fields mapped as long in all underlying indices?

Christian

My index is an index with multiple index_type. All the relative items are put to a 'test' index_type. When I visualize, I use a search pattern as "_type:test" under the index.
Is this a wrong way to deal? Next I will try to create a completely new index and see what will happen.