persistent-mysql-haskell 0.3.4.1 → 0.3.5

raw patch · 4 files changed

+25/−30 lines, 4 filesPVP ok

version bump matches the API change (PVP)

API changes (from Hackage documentation)

Files

• ChangeLog.md +3/−0
• Database/Persist/MySQL.hs +17/−28
• README.md +4/−1
• persistent-mysql-haskell.cabal +1/−1

@@ -1,3 +1,6 @@+## 0.3.5+- Updated `selectSource` implementation to stream results instead of loading everything into memory.+ ## 0.3.4.1 - Fix a haddock issue down-streamed from [#693](https://github.com/yesodweb/persistent/pull/693). 

@@ -56,6 +56,7 @@  import Data.Conduit import qualified Data.ByteString.Lazy as BS+import qualified Data.Conduit as C import qualified Data.Conduit.List as CL import qualified Data.Map as Map import qualified Data.Text as T@@ -208,40 +209,28 @@ query' conn qry [] = MySQL.query_ conn qry query' conn qry ps = MySQL.query  conn qry ps --- | Execute an statement that does return results.  The results--- are fetched all at once and stored into memory.+-- | Execute an statement that does return results.+-- unlike @persistent-mysql@, we actually _stream_ results. withStmt' :: MonadIO m           => MySQL.MySQLConn           -> MySQL.Query           -> [PersistValue]-          -> Acquire (Source m [PersistValue])-withStmt' conn query vals = do-    result <- mkAcquire createResult releaseResult-    return $ fetchRows result >>= CL.sourceList+          -> Acquire (C.Source m [PersistValue])+withStmt' conn query vals+  = fetchRows <$> mkAcquire createResult releaseResult   where-    createResult = return $ query' conn query (map P vals)-    releaseResult _ = return ()--    fetchRows result = liftIO $ do+    createResult = query' conn query (map P vals)+    releaseResult (_, is) = Streams.skipToEof is+    fetchRows (fields, is) = CL.unfoldM getVal is+      where       -- Find out the type of the columns-      (fields, is) <- result-      -- let getters = [ maybe PersistNull (getGetter f f . Just) | f <- fields]-      let getters = fmap getGetter fields-          convert = use getters-            where use (g:gs) (col:cols) =-                    let v  = g col-                        vs = use gs cols-                    in v `seq` vs `seq` (v:vs)-                  use _ _ = []--      -- Ready to go!-      let go acc = do-            row <- Streams.read is-            case row of-              Nothing  -> return (acc [])-              (Just r) -> let converted = convert r-                    in converted `seq` go (acc . (converted:))-      go id+          getters = fmap getGetter fields+          convert = zipWith (\g -> \c -> g c) getters+          getVal s = do+            v <- liftIO $ Streams.read s+            case v of+              (Just r)  -> pure $ Just (convert r, s)+              _         -> pure Nothing  -- | Encode a Haskell bool into a MySQLValue encodeBool :: Bool -> MySQL.MySQLValue

@@ -20,12 +20,15 @@  - better portability and possible static compilation of an entire project that uses `persistent-mysql`. +- result streaming support means persistent [`selectSource` streams data from database](http://www.jakubkonka.com/2014/01/23/conduit-haskell.html). Effectively addressing [#657 selectSource does not stream results](https://github.com/yesodweb/persistent/issues/657). +- a newtype-d `MySQLConnectInfo` allows adding configuring _how_ persistent and the underlying driver are glued. Ex: [#679](https://github.com/yesodweb/persistent/issues/679) can be elegantly addressed in this library.+ Personal experience on replacing `mysql-simple` with `mysql-haskell` in a project:  - Performance gains consistent with benchmark. -- Smoother deployment to [Amazon AMI/EC2](https://en.wikipedia.org/wiki/Amazon_Machine_Image), since `mysql` appears to have a hard dependency on the oracle version of `libmysqlclient` that does not work with the open source variant that is available by default on EC2 (and possibly on other cloud providers).+- Smoother deployment to [AWS](https://en.wikipedia.org/wiki/Amazon_Machine_Image), since `mysql` appears to have a hard dependency on the oracle version of `libmysqlclient` that does not work with the open source variant that is available by default on Amazon Linux (and possibly on other Linux distros).  ### Potential issues moving from persistent-mysql to persistent-mysql-haskell 

@@ -1,5 +1,5 @@ name:            persistent-mysql-haskell-version:         0.3.4.1+version:         0.3.5 license:         MIT license-file:    LICENSE author:          Naushadh <naushadh@protonmail.com>, Felipe Lessa <felipe.lessa@gmail.com>, Michael Snoyman