{-# LANGUAGE OverloadedStrings #-}
{-# LANGUAGE QuasiQuotes #-}

module PGExtras.Queries.TableCacheHit (tableCacheHitSQL, displayTableCacheHit) where

import PGExtras.Helpers (maybeText, maybeInt)
import Database.PostgreSQL.Simple
import Text.RawString.QQ
import qualified Data.Text as Text
import Control.Monad (forM_)
import Data.List (intercalate)

tableCacheHitSQL :: Query
tableCacheHitSQL :: Query
tableCacheHitSQL = [r|SELECT
  relname AS name,
  heap_blks_hit AS buffer_hits,
  heap_blks_read AS block_reads,
  heap_blks_hit + heap_blks_read AS total_read,
  CASE (heap_blks_hit + heap_blks_read)::float
    WHEN 0 THEN 'Insufficient data'
    ELSE (heap_blks_hit / (heap_blks_hit + heap_blks_read)::float)::text
  END ratio
FROM
  pg_statio_user_tables
ORDER BY
  heap_blks_hit / (heap_blks_hit + heap_blks_read + 1)::float DESC;|]

displayTableCacheHit :: [(Maybe Text.Text, Maybe Int, Maybe Int, Maybe Int, Maybe Text.Text)] -> IO ()
displayTableCacheHit :: [(Maybe Text, Maybe Int, Maybe Int, Maybe Int, Maybe Text)]
-> IO ()
displayTableCacheHit rows :: [(Maybe Text, Maybe Int, Maybe Int, Maybe Int, Maybe Text)]
rows = do
  String -> IO ()
putStrLn (String -> IO ()) -> String -> IO ()
forall a b. (a -> b) -> a -> b
$ String
description
  String -> IO ()
putStrLn (String -> IO ()) -> String -> IO ()
forall a b. (a -> b) -> a -> b
$ String -> [String] -> String
forall a. [a] -> [[a]] -> [a]
intercalate " | " [String]
tableHeaders
  [(Maybe Text, Maybe Int, Maybe Int, Maybe Int, Maybe Text)]
-> ((Maybe Text, Maybe Int, Maybe Int, Maybe Int, Maybe Text)
    -> IO ())
-> IO ()
forall (t :: * -> *) (m :: * -> *) a b.
(Foldable t, Monad m) =>
t a -> (a -> m b) -> m ()
forM_ [(Maybe Text, Maybe Int, Maybe Int, Maybe Int, Maybe Text)]
rows (((Maybe Text, Maybe Int, Maybe Int, Maybe Int, Maybe Text)
  -> IO ())
 -> IO ())
-> ((Maybe Text, Maybe Int, Maybe Int, Maybe Int, Maybe Text)
    -> IO ())
-> IO ()
forall a b. (a -> b) -> a -> b
$ \(arg1 :: Maybe Text
arg1, arg2 :: Maybe Int
arg2, arg3 :: Maybe Int
arg3, arg4 :: Maybe Int
arg4, arg5 :: Maybe Text
arg5) ->
    String -> IO ()
putStrLn (String -> IO ()) -> String -> IO ()
forall a b. (a -> b) -> a -> b
$ Maybe Text -> String
maybeText(Maybe Text
arg1) String -> String -> String
forall a. [a] -> [a] -> [a]
++ " | " String -> String -> String
forall a. [a] -> [a] -> [a]
++ Maybe Int -> String
maybeInt(Maybe Int
arg2) String -> String -> String
forall a. [a] -> [a] -> [a]
++ " | " String -> String -> String
forall a. [a] -> [a] -> [a]
++ Maybe Int -> String
maybeInt(Maybe Int
arg3) String -> String -> String
forall a. [a] -> [a] -> [a]
++ " | " String -> String -> String
forall a. [a] -> [a] -> [a]
++ Maybe Int -> String
maybeInt(Maybe Int
arg4) String -> String -> String
forall a. [a] -> [a] -> [a]
++ " | " String -> String -> String
forall a. [a] -> [a] -> [a]
++ Maybe Text -> String
maybeText(Maybe Text
arg5)

description :: [Char]
description :: String
description = "Calculates your cache hit rate for reading tables"

tableHeaders :: [[Char]]
tableHeaders :: [String]
tableHeaders = ["name", "buffer_hits", "block_reads", "total_read", "ratio"]