Dmitry,
I'm not directly familiar with Takusen or its use with OracleDB, but I
would hazard a guess that the withSession is doing FFI resource management
and that resources obtained inside the withSession environment are no
longer valid outside of the withSession.
If this is the case then I would expect the following to work:
replicateM 2 (do
withSession (connect "x" "x" "x") (do
res <- doQuery ...
liftIO $ print res
)
)
If this really is the case then it seems that withSession shouldn't be
exporting FFI-based resources.
-KQ
On Wed, 01 Jun 2011 07:44:10 -0700, Dmitry Olshansky
Hello,
Could anyone explain strange behavior of Takusen with OracleDB (OraClient 11.x)? Several sequential sessions give "Seqmentation Fault" error. In case of nested sessions it works well.
{-# LANGUAGE ScopedTypeVariables #-} module Main where import Database.Oracle.Enumerator import Control.Monad(replicateM) import Control.Monad.Trans(liftIO) main = do {- -- This gives an Segmentation Fault for the second session
replicateM 2 (do res <- withSession (connect "x" "x" "x") (do doQuery (sql "SELECT dummy FROM dual") (\(d::String) (_::Maybe String) -> result' $ Just d) Nothing ) print res ) -}
-- This is works well
withSession (connect "x" "x" "x") (do r1 <- doQuery (sql "SELECT dummy FROM dual") (\(d::String) (_::Maybe String) -> result' $ Just d) Nothing liftIO $ print r1 liftIO $ withSession (connect "x" "x" "x") (do r2 <- doQuery (sql "SELECT dummy FROM dual") (\(d::String) (_::Maybe String) -> result' $ Just d) Nothing liftIO $ print r2 ) ) Best regards, Dmitry
-- -KQ