Folks, I have a huge space leak someplace and I suspect this code. The SrvServerInfo data structure is something like 50K compressed or uncompressed byte data before unpickling. My thousands of bots issue this request at least once and I almost run out of memory with 100 bots on a 1Gb machine on FreeBSD. Do I need deepSeq somewhere below? This is the read. read :: Handle -> (SSL, BIO, BIO) -> IO Command read h _ = do sa <- emptyByteArray 4 hGetArray h sa 4 (size', _) <- unpickle endian32 sa 0 let size = fromIntegral $ size' - 4 packet <- emptyByteArray size hGetArray h packet size unstuff packet 0 I suspect that I need to deepSeq cmd'' instead of return $! cmd'' unstuff :: MutByteArray -> Index -> IO Command unstuff array ix = do (kind, ix1) <- unpickle puCmdType array ix (cmd', _) <- unpickle (puCommand kind) array ix1 case cmd' of InvalidCommand -> do fail $ "unstuff: Cannot parse " ++ show array SrvCompressedCommands sz bytes -> do bytes' <- uncompress bytes (fromIntegral sz) cmd'' <- unstuff bytes' 4 return $! cmd'' _ -> return cmd' This is where the list of active tables is converted to a table id list of [Word32]. pickTable _ filters (Cmd cmd@(SrvServerInfo {})) = do let tables = filter (tableMatches filters) $ activeTables cmd ids = map tiTableID tables case tables of [] -> fail $ "pickTable: No tables found: " ++ show filters _ -> do pop stoptimer "pickTable" return $! Eat $! Just $! Custom $! Tables $! ids This is where the table id list of [Word32] is consumed. takeEmptySeat _ aff_id _ (Custom (Tables ids@(table:rest))) = do trace 85 $ "takeEmptySeat: " ++ show (length ids) ++ " tables found" trace 100 $ "takeEmptySeat: tables: " ++ showTables ids trace 85 $ "takeEmptySeat: trying table# " ++ show table w <- get put_ $ w { tables_to_try = rest } push "goToTable" $ goToTable table aff_id -- kick off goToTable return $ Eat $ Just Go This is the SrvServerInfo structure. | SrvServerInfo { activeTables :: ![TableInfo], -- Word16/ removedTables :: ![Word32], -- Word16/ version :: !Int32 } And this is the table info itself. data TableInfo = TableInfo { tiAvgPot :: !Word64, tiNumPlayers :: !Word16, tiWaiting :: !Word16, tiPlayersFlop :: !Word8, tiTableName :: !String, tiTableID :: !Word32, tiGameType :: !GameType, tiInfoMaxPlayers :: !Word16, tiIsRealMoneyTable :: !Bool, tiLowBet :: !Word64, tiHighBet :: !Word64, tiMinStartMoney :: !Word64, tiMaxStartMoney :: !Word64, tiGamesPerHour :: !Word16, tiTourType :: !TourType, tiTourID :: !Word32, tiBetType :: !BetType, tiCantReturnLess :: !Word32, tiAffiliateID :: ![Word8], tiLangID :: !Word32 } deriving (Show, Typeable) Thanks, Joel -- http://wagerlabs.com/