fix: unnecessary set default_transaction_isolation

CHANGELOG.md

@@ -15,6 +15,7 @@ This project adheres to [Semantic Versioning](http://semver.org/).
  - #2939, Fix `count=exact` not being included in `Preference-Applied` - @steve-chavez
  - #2800, Fix not including to-one embed resources that had a `NULL` value in any of the selected fields when doing null filtering on them - @laurenceisla
  - #2846, Fix error when requesting `Prefer: count=<type>` and doing null filtering on embedded resources - @laurenceisla
+ - #2846, Fix setting `default_transaction_isolation` unnecessarily - @steve-chavez
 
 ## [11.2.0] - 2023-08-10
 

src/PostgREST/Config/Database.hs

@@ -154,7 +154,7 @@ queryRoleSettings prepared =
       select
         kv.rolname,
         i.value as iso_lvl,
-        array_agg(row(kv.key, kv.value)) filter (where key <> 'default_transation_isolation') as role_settings
+        coalesce(array_agg(row(kv.key, kv.value)) filter (where key <> 'default_transaction_isolation'), '{}') as role_settings
       from kv_settings kv
       join pg_settings ps on ps.name = kv.key and ps.context = 'user'
       left join iso_setting i on i.rolname = kv.rolname