diff --git a/hasql.cabal b/hasql.cabal
--- a/hasql.cabal
+++ b/hasql.cabal
@@ -1,7 +1,7 @@
 name:
   hasql
 version:
-  0.20
+  0.20.0.1
 category:
   Hasql, Database, PostgreSQL
 synopsis:
diff --git a/library/Hasql/Core/Batch.hs b/library/Hasql/Core/Batch.hs
--- a/library/Hasql/Core/Batch.hs
+++ b/library/Hasql/Core/Batch.hs
@@ -22,16 +22,16 @@
     Batch (\_ psr -> (pure x, psr))
   {-# INLINABLE (<*>) #-}
   (<*>) (Batch left) (Batch right) =
-    Batch (\idt psr -> case left idt psr of
+    Batch (\(!idt) (!psr) -> case left idt psr of
       (leftRequest, leftPsr) -> case right idt leftPsr of
         (rightRequest, rightPsr) -> (leftRequest <*> rightRequest, rightPsr))
 
 statement :: A.Statement params result -> params -> Batch result
 statement (A.Statement template paramOIDs paramBytesBuilder1 paramBytesBuilder2 interpretResponses1 interpretResponses2 prepared) params =
-  Batch $ \idt psr ->
+  Batch $ \(!idt) (!psr) ->
   if prepared
     then case D.lookupOrRegister template paramOIDs psr of
-      (newOrOldName, newPsr) ->
+      (!newOrOldName, !newPsr) ->
         let
           request =
             case newOrOldName of
diff --git a/library/Hasql/Core/ParseDataRow.hs b/library/Hasql/Core/ParseDataRow.hs
--- a/library/Hasql/Core/ParseDataRow.hs
+++ b/library/Hasql/Core/ParseDataRow.hs
@@ -25,13 +25,13 @@
 
 nullableColumn :: D.BinaryParser column -> ParseDataRow (Maybe column)
 nullableColumn parser =
-  ParseDataRow 1 $ \vec index ->
+  ParseDataRow 1 $ \vec !index ->
   either (Left . mappend ("Column " <> (fromString . show) index <> ": ")) Right $
   traverse (D.run parser) (A.unsafeIndex vec index)
 
 column :: D.BinaryParser column -> ParseDataRow column
 column parser =
-  ParseDataRow 1 $ \vec index ->
+  ParseDataRow 1 $ \vec !index ->
   either (Left . mappend ("Column " <> (fromString . show) index <> ": ")) Right $
   case A.unsafeIndex vec index of
     Just bytes -> D.run parser bytes
diff --git a/profiling/Main.hs b/profiling/Main.hs
--- a/profiling/Main.hs
+++ b/profiling/Main.hs
@@ -17,7 +17,12 @@
   do
     connection <- connect
     traceEventIO "START Session"
-    Right !result <- fmap force <$> A.session connection (session 10 10 100)
+    Right !result <- fmap force <$> A.session connection (session 50 10 100)
+    Right !result <- fmap force <$> A.session connection (session 50 10 100)
+    Right !result <- fmap force <$> A.session connection (session 10 50 100)
+    Right !result <- fmap force <$> A.session connection (session 50 10 100)
+    Right !result <- fmap force <$> A.session connection (session 10 50 100)
+    Right !result <- fmap force <$> A.session connection (session 10 50 100)
     traceEventIO "STOP Session"
     return ()
 
diff --git a/tests/Main.hs b/tests/Main.hs
--- a/tests/Main.hs
+++ b/tests/Main.hs
@@ -23,13 +23,13 @@
 connect :: IO A.Connection
 connect =
   do
-    openingResult <- A.open (A.TCPConnectionSettings "localhost" 5432) "postgres" "" Nothing handleErrorOrNotification
+    openingResult <- A.open (A.TCPConnectionSettings "localhost" 5432) "postgres" "" Nothing handleNotification
     case openingResult of
       Left error -> fail (showString "Can't connect: " (show error))
       Right connection -> return connection
   where
-    handleErrorOrNotification x =
-      putStrLn ("Async event: " <> show x)
+    handleNotification x =
+      putStrLn ("Notification: " <> show x)
 
 runTests :: A.Connection -> IO ()
 runTests connection =