Use a nullable column to speed up migration

Application.hs

@@ -403,7 +403,11 @@ fixSnapSlugs =
 
 setCorePackages :: MonadIO m => ReaderT SqlBackend m ()
 setCorePackages =
-    updateWhere [PackageName' <-. defaultCorePackages] [PackageCore =. True]
+    updateWhere
+        [ PackageName' <-. defaultCorePackages
+        , PackageCore ==. Nothing
+        ]
+        [PackageCore =. Just True]
   where
     defaultCorePackages = map PackageName $ words =<<
         [ "ghc hoopl bytestring unix haskeline Cabal base time xhtml"

Handler/StackageHome.hs

@@ -146,7 +146,7 @@ getStackageCabalConfigR slug = do
         toBuilder '\n'
 
     constraint p
-        | packageCore p = toBuilder $ asText " installed"
+        | Just True <- packageCore p = toBuilder $ asText " installed"
         | otherwise = toBuilder (asText " ==") ++
                       toBuilder (toPathPiece $ packageVersion p)
 

Handler/UploadStackage.hs

@@ -156,7 +156,7 @@ putUploadStackageR = do
                                         , packageVersion = version
                                         , packageOverwrite = overwrite
                                         , packageHasHaddocks = False
-                                        , packageCore = name `member` cores
+                                        , packageCore = Just $ name `member` cores
                                         }
 
                                     setAlias

config/models

@@ -44,7 +44,7 @@ Package
     version Version
     hasHaddocks Bool default=true
     overwrite Bool
-    core Bool default=false
+    core Bool Maybe -- use Maybe to speed up migration
 
 Tag
     package PackageName