Comment Comment by orf > If you have pid,{name:’val’, others...}. And an index of name with a million John and one Jane. Good luck getting fast results.Fast results: https://dbfiddle.uk/?rdbms=postgres_10&fiddle=dd9370966b1528....Postgres does actually keep statistics on json columns, but if you've got a functional index on the table and the query uses it then it doesn't matter if there is one "jane" and a million "johns". You're looking up a key in a btree index. parent orf 6 years ago
Fast results: https://dbfiddle.uk/?rdbms=postgres_10&fiddle=dd9370966b1528....
Postgres does actually keep statistics on json columns, but if you've got a functional index on the table and the query uses it then it doesn't matter if there is one "jane" and a million "johns". You're looking up a key in a btree index.