example.hs

sitesQuery :: Query
sitesQuery = "select id, name from sites"

queryUsersAndCreateCheckpoints :: IO ()
queryUsersAndCreateCheckpoints = do
  conn <- mysqlConnect -- my own helper function
  statement <- prepareStmt conn sitesQuery
  results <-
    queryStmtResults conn statement [] >>= -- Query all the sites so they can be processed concurrently
    Streams.toList -- The list is small, so we need no streaming
  closeStmt conn statement
  close conn
  files <- mapConcurrently processSingleSite results
  ...

processSingleSite :: (Int, Text) -> IO (Maybe Text)
processSingleSite siteId, siteName) = do
  putStrLn ("Processing site: " ++ siteName)
  ...