Fix #1141, app.settings resetting on pool timeout (#1169)

* Add test for ensuring app.settings don't reset

src/PostgREST/DbStructure.hs

@@ -10,7 +10,6 @@ module PostgREST.DbStructure (
 , accessibleProcs
 , schemaDescription
 , getPgVersion
-, fillSessionWithSettings
 ) where
 
 import qualified Hasql.Decoders                as HD
@@ -33,9 +32,6 @@ import           GHC.Exts                      (groupWith)
 import           Protolude
 import           Unsafe (unsafeHead)
 
-import           Data.Functor.Contravariant    (contramap)
-import           Contravariant.Extras          (contrazip2)
-
 getDbStructure :: Schema -> PgVersion -> H.Session DbStructure
 getDbStructure schema pgVer = do
   tabs      <- H.query () allTables
@@ -764,17 +760,3 @@ getPgVersion = H.query () $ H.statement sql HE.unit versionRow False
   where
     sql = "SELECT current_setting('server_version_num')::integer, current_setting('server_version')"
     versionRow = HD.singleRow $ PgVersion <$> HD.value HD.int4 <*> HD.value HD.text
-
-fillSessionWithSettings :: [(Text, Text)] -> H.Session ()
-fillSessionWithSettings settings =
-    -- Send all of the config settings to the set_config function, using pgsql's `unnest` to transform arrays of values
-    H.query settings $ H.statement "SELECT set_config(k, v, false) FROM unnest($1, $2) AS f1(k, v)" encoder HD.unit False
-
-  where
-    -- Take a list of (key, value) pairs and encode each as an array to later bind to the query
-    -- see Insert Many section at https://hackage.haskell.org/package/hasql-1.1.1/docs/Hasql-Encoders.html
-    encoder = contramap L.unzip $ contrazip2 (vector HE.text) (vector HE.text)
-      where
-        vector value =
-          HE.value $ HE.array $ HE.arrayDimension foldl' $ HE.arrayValue value
-