These are the two relevant patches that I know of (there might be more): 1. https://github.com/postgres/postgres/commit/3838fa269c15706df2b85ce2d6af8aacd561165

These are the two relevant patches that I know of (there might be more): 1. https://github.com/postgres/postgres/commit/3838fa269c15706df2b85ce2d6af8aacd5611655 https://github.com/postgres/postgres/commit/3838fa269c15706d... 2. https://github.com/postgres/postgres/commit/121d2d3d70ecdb2113b340c5f3b99a61341291af https://github.com/postgres/postgres/commit/121d2d3d70ecdb21... It causes much less CPU overhead on the receiving side of a copy when receiving big JSON blobs.