When I try to update the column with large json value (of type jsonb). I am getting following error.
[54000] ERROR: total size of jsonb array elements exceeds the maximum of 268435455 bytes
Is there any way to fix it or increase jsonb size?
This isn't a bug and the only option to increase it is to change "JENTRY_OFFLENMASK" in src/include/utils/jsonb.h (and while I'm not a hacker I doubt its that simple).
If you are willing to go down the hacker path you should post a new message to the -hackers list discussing your desire.
Otherwise the limit here seems to be due to having too many array elements - converting each element into a single database row will probably work and likely will perform considerably better regardless, though its difficult to know for sure without more detail about the structure of the json.