About Data too Large Error

Hi,we store emails in ES and always need to sort search result with the "sendDate" field.

However, as there is so many email belong to a user, it always return :"Data too large, data for [sendDate] would be larger than limit of [10307921510/9.5gb]".

Is there something I can do to let it work?

If I set the 'boost = 10' to sendDate and 'boost = 0' to other field when create Mapping, can it help us to solve the problem?