Exporting data from field with HUGE content

I want to export my ES (v6.0.0) data to csv, for which I have the tool (es2csv). However, one of the fields (message) stores commit messages, and quite a lot of the entries are HUGE. The content can run to multiple pages. I know this should've been taken care of during indexing, but this data comes from a third party. Anyway, the problem is that while exporting the data, the tool just fails to accommodate those huge messages, and just goes haywire. It simply skips quite a lot of entries that follow the problematic entry. Furthermore, the size of the exported file can be in GBs.

So, how can I resolve or sidestep this problem? Some of the probable solutions I was thinking about are as follows:

  1. A tool where I can specify character limitations on specific fields while exporting them.: Haven't come across any, yet
  2. Reindex/Clone the current index with a specific mapping for the message field, where I can place those character limitations: Can't figure out the exact steps for this

Any help would be appreciated.