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by Psyonic 3546 days ago
jsonb_set is available now in postgres 9.5: https://www.postgresql.org/docs/9.5/static/functions-json.ht...
1 comments

but that's not partial update. this will update the entire document(blob).
Postgres' MVCC architecture makes the idea of 'partial updates' kind of meaningless. An update to any postgres column is equivalent to a DELETE followed by an INSERT and will result in a new row on disk, leaving the old row to be vacuumed later.
Just to clarify: s/architecture/implementation/

InnoDB is MVCC too, but does an update in place with relocation of the old row to UNDO space. There are pros and cons to both approaches.