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{-# LANGUAGE OverloadedStrings #-}
module Main where
import Database.PostgreSQL.Simple
import qualified Database.PostgreSQL.Simple.Vector as V
import qualified Database.PostgreSQL.Simple.Vector.Unboxed as VU
import System.Environment (getArgs)
import Data.Foldable (Foldable, foldl')
import qualified Data.Vector.Unboxed as VU
main :: IO ()
main = do
args <- getArgs
conn <- connectPostgreSQL ""
case args of
("vector":_) -> do
result <- V.query_ conn "SELECT * FROM generate_series(1, 10000000);"
print (process result)
("unboxed":_) -> do
-- dummy column
result <- VU.query_ conn "SELECT (NULL :: VOID), * FROM generate_series(1, 10000000);"
print (process' result)
_ -> do
result <- query_ conn "SELECT * FROM generate_series(1, 10000000);"
print (process result)
process :: Foldable f => f (Only Int) -> Int
process = foldl' (\x (Only y) -> max x y) 0
process' :: VU.Vector ((), Int) -> Int
process' = VU.foldl' (\x (_, y) -> max x y) 0
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