大约有多快JSON - > Postgres 9.4中的JSONB列转换

I'm looking to migrate from Postgres 9.3 to 9.4, and have a lot of data in JSON columns. While it's fine, I wanted to have a look at migrating to the more efficient column storage (which JSONB seems to be — a really exciting piece of tech!).I'm looking to migrate from Postgres 9.3 to 9.4