On 2022-06-24 Fr 20:18, Andres Freund wrote: > Hi, > > On 2022-06-24 08:47:09 +0000, Jelte Fennema wrote: >> To test performance of this change I used COPY BINARY from a JSONB table >> into another, containing fairly JSONB values of ~15kB. > This will have a lot of other costs included (DML is expensive). I'd suggest > storing the json in a text column and casting it to json[b], with a filter > ontop of the json[b] result that cheaply filters it away. That should end up > spending nearly all the time somewhere around json parsing. > > It's useful for things like this to include a way for others to use the same > benchmark... > > I tried your patch with: > > DROP TABLE IF EXISTS json_as_text; > CREATE TABLE json_as_text AS SELECT (SELECT json_agg(row_to_json(pd)) as t > FROM pg_description pd) FROM generate_series(1, 100); > VACUUM FREEZE json_as_text; > > SELECT 1 FROM json_as_text WHERE jsonb_typeof(t::jsonb) = 'not me';
I've been doing some other work related to json parsing and John referred me to this. But it's actually not the best test for pure json parsing - casting to jsonb involves some extra work besides pure parsing. Instead I've been using this query with the same table, which should be almost all json parsing: select 1 from json_as_text where t::json is null; cheers andrew -- Andrew Dunstan EDB: https://www.enterprisedb.com