Very slow select queries (Ignoring Indexing?)

I have a table with 1M rows that has the following index:

psql -U user -d db -c “SELECT * FROM pg_indexes WHERE tablename = ‘messages’;”
schemaname |  tablename  |         indexname         | tablespace |                                          indexdef
------------+-------------+---------------------------+------------+---------------------------------------------------------------------------------------------
public     | messages| updates_timestamp_idx |            | CREATE INDEX updates_timestamp_idx ON public.updates USING btree (“timestamp” DESC)

When I do a select query for the first 10 entries in desc order on the timestamp key on PSQL it runs in 0.039s while hasura takes 4.735s.

This difference is orders of magnitude bigger. Any idea what’s the reason?

P.S. It returns a different result as well. Maybe it doesn’t use the indexes at all?

Also, example times from a query on a non indexed column from 1. hasura, 2. psql, 3. postgrest

[theshire-io]

Please consider adding a section in the docs about optimizations like this so that this kind of info does not remain “out of sight” in the issues.

[slowr]

upon logging the generated queries I found out that the root of the evil was the NULLS LAST statement that is added in the query. So as suggested in #657 I used the NULLS FIRST approach and the query is working as expected.

Is there a reason that the default is NULLS LAST and this cause the indexes to not be used? Maybe make the _asc and _desc to generate the correct query in order to use the indexes (like NULLS LAST for _asc and NULLS FIRST for _desc, or an enum for no NULLS handling at all)?