PostgreSQL 13.0. You’d have to be specific about the configs you’re looking for, I’m using Postgres.app (postgresapp.com <http://postgresapp.com/>) and am uncertain if it’s distributed with non-default configs.
But, a quick grep shows these items that are configured: max_wal_size = 1GB min_wal_size = 80MB shared_buffers = 128MB work_mem is not configured so presumably it’s the default of 4MB. I’ll try the temp tables. That seems familiar to what I found searching online - are you suggesting that as a permanent solution, or just as a means to better analyze performance? Thanks, Matt > On Oct 21, 2020, at 1:25 PM, Michael Lewis <mle...@entrata.com> wrote: > > Version? What is the value for work_mem and other configs that are > non-default? I see some estimates that are rather off like - > > -> Nested Loop (cost=0.26..4.76 rows=100 width=148) (actual > time=183.906..388716.550 rows=8935 loops=1) > Buffers: shared hit=53877 dirtied=2 > -> Function Scan on json_to_recordset x (cost=0.01..1.00 > rows=100 width=128) (actual time=130.645..142.316 rows=8935 loops=1) > -> Function Scan on get_transaction_type_by_id > bank_transaction_type (cost=0.25..0.26 rows=1 width=4) (actual > time=0.154..0.156 rows=1 loops=8935) > Buffers: shared hit=18054 > > Sometimes putting data into a temp table and analyzing it can be rather > helpful to ensure the planner has statistics on the number of records, > ndistinct, most common values, etc. I would try doing that with the result of > json_to_recordset and skipping the function call to > get_transaction_type_by_id until later, just to see how it performs. > > That said, it seems like a hardcoded estimate from json_to_recordset is 100 > perhaps. I haven't checked source code, but I know when defining a set > returning function, there is a ROWS option which provides the planner a > static value to assume will come out of that function so it would make sense > perhaps.
