Doc values for @timestamp and geo.location

Elastic Stack Elasticsearch
1

I am running into high JVM on my data nodes. I noticed @timestamp and geo.location seems to be taking up 2gb of my heap. Are there any ill effects of turning on doc values for these two fields? My use case is logstash indices with logs

     "indices": {
        "fielddata": {
           "memory_size_in_bytes": 1765178740,
           "evictions": 0,
           "fields": {
              "host": {
                 "memory_size_in_bytes": 0
              },
              "@timestamp": {
                 "memory_size_in_bytes": 1287128696
              },
              "geoip.location": {
                 "memory_size_in_bytes": 478050044
              },
              "username": {
                 "memory_size_in_bytes": 0
2

Both fields are analyzed so doc values won't work.

3

Nothing can be done then?
I ran a few more queries and found that those fielddata were taking 14GB on the heap across all indices.

4

Kind of confused right now.
What is weird is that Kibana 4-> Settings -> Indices tab says @timestamp and geo.location are not analyzed fields.

5

a person in the IRC said that only strings are analyzed. Sounds like it will be ok to make @timestamp a doc value?