I started seeing this error the other day when running CDRsv1.GetCDRs on the CGrateS API:

SERVER_ERROR: unexpected end of JSON input

It seemed related to certain CDRs in the cdrs table of StoreDB.

After some digging, I found the stupid simple problem:

I’d written too much data to extra_fields, leading MySQL to cut off the data mid way through, meaning it couldn’t be reconstructed as JSON by CGrateS again.

Like the rounding issue I had, this wasn’t an issue with CGrateS but with MySQL.

Quick fix:

sudo mysql cgrates -e "ALTER TABLE cdrs MODIFY extra_fields LONGTEXT;"

And new fields can exceed this length without being cut off.