We have recently upgraded our older ELK cluster which was on 6.3.2 to 6.8.23. We have tested the functionalities and messages are loading, Dashboards are working fine, and search in Discover is also working
But if we try to visualize something. No Result is obtained after the upgrade date. The visualize also shows data before the upgrade.
There is no error shown in kibana logs while the following logs are received in Elasticsearch logs
Caused by: java.lang.IllegalArgumentException: Fielddata is disabled on text fields by default. Set fielddata=true on [info.type] in order to load fielddata in memory by uninverting the inverted index. Note that this can however use significant memory. Alternatively use a keyword field instead.
Kindly suggest a method to rectify our issue so that the we could get results in visulaize also