hw-json

hw-json is a succinct JSON parsing library. It uses succinct data-structures to allow traversal of large JSON strings with minimal memory overhead.

For an example, see app/Main.hs

Prerequisites

• Install haskell-stack.
• Install hlint (eg. stack install hlint)

Memory benchmark

Parsing large Json files in Scala with Argonaut

      S0U       EU           OU       MU     CCSU CMD
--------- --------- ----------- -------- -------- ---------------------------------------------------------------
      0.0  80,526.3    76,163.6 72,338.6 13,058.6 sbt console
      0.0 536,660.4    76,163.6 72,338.6 13,058.6 import java.io._, argonaut._, Argonaut._
      0.0 552,389.1    76,163.6 72,338.6 13,058.6 val file = new File("/Users/jky/Downloads/78mbs.json"
      0.0 634,066.5    76,163.6 72,338.6 13,058.6 val array = new Array[Byte](file.length.asInstanceOf[Int])
      0.0 644,552.3    76,163.6 72,338.6 13,058.6 val is = new FileInputStream("/Users/jky/Downloads/78mbs.json")
      0.0 655,038.1    76,163.6 72,338.6 13,058.6 is.read(array)
294,976.0 160,159.7 1,100,365.0 79,310.8 13,748.1 val json = new String(array)
285,182.9 146,392.6 1,956,264.5 82,679.8 14,099.6 val data = Parse.parse(json)
                    ***********

Parsing large Json files in Haskell with Aeson

Mem (MB) CMD
-------- ---------------------------------------------------------
      54 import Control.DeepSeq
      64 import Data.Aeson
      64 import qualified Data.ByteString.Lazy as BSL
      66 json78m <- BSL.readFile "../data/78mb.json"
     167 let !x = deepseq json78m json78m
    1207 let !y = decode json78m :: Maybe Value

Parsing large Json files in Haskell with hw-json

Mem (MB) CMD
-------- ---------------------------------------------------------
      57 import           Foreign
      58 import           Control.Monad
      59 import qualified Data.ByteString as BS
      76 import qualified Data.Vector.Storable as DVS
      77 import           Data.Word
      77 import           HaskellWorks.Data.BalancedParens.Simple
      77 import           HaskellWorks.Data.Bits.BitShown
      77 import           HaskellWorks.Data.FromForeignRegion
      81 import           HaskellWorks.Data.Json.Succinct.Cursor
      82 import           HaskellWorks.Diagnostics
      83 import           System.IO.MMap
      88 (fptr :: ForeignPtr Word8, offset, size) <- mmapFileForeignPtr "../data/78mbs.json" ReadOnly Nothing
     276 cursor <- measure (fromForeignRegion (fptr, offset, size) :: JsonCursor BS.ByteString (DVS.Vector Word64) (SimpleBalancedParens (DVS.Vector Word64)))

Examples

Performance example

(This section out of date)

import Foreign
import qualified Data.Vector.Storable as DVS
import qualified Data.ByteString as BS
import qualified Data.ByteString.Internal as BSI
import System.IO.MMap
import Data.Word
import System.CPUTime
(fptr :: ForeignPtr Word8, offset, size) <- mmapFileForeignPtr "/Users/jky/Downloads/78mbs.json" ReadOnly Nothing
cursor <- measure (fromForeignRegion (fptr, offset, size) :: JsonCursor BS.ByteString (DVS.Vector Word64) (SimpleBalancedParens (DVS.Vector Word64)))
let !bs = BSI.fromForeignPtr (castForeignPtr fptr) offset size
x <- measure $ jsonBsToInterestBs bs
let !y = BS.concat (unescape' "" [bs])

import Foreign
import qualified Data.Vector.Storable as DVS
import qualified Data.ByteString as BS
import qualified Data.ByteString.Internal as BSI
import System.IO.MMap
import Data.Word
import System.CPUTime
(fptr :: ForeignPtr Word8, offset, size) <- mmapFileForeignPtr "/Users/jky/Downloads/part40.json" ReadOnly Nothing
let !bs = BSI.fromForeignPtr (castForeignPtr fptr) offset size
x <- measure $ BS.concat $ blankedJsonToInterestBits $ blankJson [bs]
x <- measure $ jsonBsToInterestBs bs

jsonTokenAt $ J.nextSibling $ J.firstChild $ J.nextSibling $ J.firstChild $ J.firstChild  cursor

Navigation example

import qualified Data.ByteString                             as BS
import           Data.String
import qualified Data.Vector.Storable                        as DVS
import           Data.Word
import           HaskellWorks.Data.Bits.BitShow
import           HaskellWorks.Data.Bits.BitShown
import           HaskellWorks.Data.FromForeignRegion
import           HaskellWorks.Data.Json.Succinct.Cursor      as C
import           HaskellWorks.Data.Json.Token
import           HaskellWorks.Data.BalancedParens.Simple
import           HaskellWorks.Data.RankSelect.Base.Rank0
import           HaskellWorks.Data.RankSelect.Base.Rank1
import           HaskellWorks.Data.RankSelect.Base.Select1
import           HaskellWorks.Data.RankSelect.Poppy512
import qualified HaskellWorks.Data.TreeCursor as TC
import           System.IO.MMap
let fc = TC.firstChild
let ns = TC.nextSibling
let pn = TC.parent
let ss = TC.subtreeSize
let cursor = "[null, {\"field\": 1}]" :: JsonCursor BS.ByteString (DVS.Vector Word64) (SimpleBalancedParens (DVS.Vector Word64))
cursor
fc cursor
(fc >=> ns) cursor

Querying example

import           Control.Monad
import qualified Data.DList as DL
import           Data.Function
import           Data.List
import           HaskellWorks.Data.Json.LoadCursor
import           HaskellWorks.Data.Micro
import           HaskellWorks.Data.MQuery
import           HaskellWorks.Data.Json.PartialValue
import           HaskellWorks.Data.Row
import           HaskellWorks.Diagnostics

!cursor <- loadJsonPartial "../data/78mb.json"
!cursor <- loadJsonWithIndex "../data/78mb.json"
!cursor <- loadJson "../data/78mb.json"
!cursor <- loadJsonWithCsPoppyIndex "../data/78mb.json"
let !json = jsonPartialJsonValueAt cursor
let q = MQuery (DL.singleton json)

measureIO $ putPretty $ q >>= item & limit 10
measureIO $ putPretty $ q >>= item & page 10 1
measureIO $ putPretty $ q >>= item >>= hasKV "founded_year" (JsonPartialNumber 2005) & limit 10
measureIO $ putPretty $ q >>= item >>= entry
measureIO $ putPretty $ q >>= item >>= entry >>= named "name" & limit 10
measureIO $ putPretty $ q >>= (item >=> entry >=> named "acquisition" >=> entry >=> named "price_currency_code")
measureIO $ putPretty $ q >>= (item >=> entry >=> named "acquisition" >=> entry >=> named "price_currency_code") & onList (uniq . sort)
measureIO $ putPretty $ q >>= (item >=> entry >=> named "acquisition" >=> entry >=> named "price_currency_code" >=> asString >=> valueOf "USD") & limit 10
measureIO $ putPretty $ q >>= (item >=> entry >=> named "acquisition" >=> having (entry >=> named "price_currency_code" >=> asString >=> valueOf "USD") >=> entry >=> named "price_amount") & limit 10
measureIO $ putPretty $ q >>= (item >=> entry >=> named "acquisition" >=> having (entry >=> named "price_currency_code" >=> asString >=> valueOf "USD") >=> entry >=> named "price_amount" >=> castAsInteger ) & limit 10
measureIO $ putPretty $ q >>= (item >=> entry >=> named "acquisition" >=> having (entry >=> named "price_currency_code" >=> asString >=> valueOf "USD") >=> entry >=> named "price_amount" >=> castAsInteger ) & aggregate sum

import           Control.Monad
import qualified Data.DList as DL
import           Data.Function
import           Data.List
import           HaskellWorks.Data.Json.LoadCursor
import           HaskellWorks.Data.Micro
import           HaskellWorks.Data.MQuery
import           HaskellWorks.Data.Json.LightJson
import           HaskellWorks.Data.Row
import           HaskellWorks.Diagnostics

!cursor <- loadJsonPartial "../data/78mb.json"
!cursor <- loadJsonWithIndex "../data/78mb.json"
!cursor <- loadJson "../data/78mb.json"
!cursor <- loadJsonWithCsPoppyIndex "../data/78mb.json"
let !json = lightJsonAt cursor
let q = MQuery (DL.singleton json)

measureIO $ putPretty $ q >>= item & limit 10
measureIO $ putPretty $ q >>= item & page 10 1
measureIO $ putPretty $ q >>= item >>= entry
measureIO $ putPretty $ q >>= item >>= entry >>= named "name" & limit 10
measureIO $ putPretty $ q >>= (item >=> entry >=> named "acquisition" >=> entry >=> named "price_currency_code" >=> asString)
measureIO $ putPretty $ q >>= (item >=> entry >=> named "acquisition" >=> entry >=> named "price_currency_code" >=> asString) & onList (uniq . sort)
measureIO $ putPretty $ q >>= (item >=> entry >=> named "acquisition" >=> entry >=> named "price_currency_code" >=> asString >=> valueOf "USD") & limit 10
measureIO $ putPretty $ q >>= (item >=> entry >=> named "acquisition" >=> having (entry >=> named "price_currency_code" >=> asString >=> valueOf "USD") >=> entry >=> named "price_amount") & limit 10
measureIO $ putPretty $ q >>= (item >=> entry >=> named "acquisition" >=> having (entry >=> named "price_currency_code" >=> asString >=> valueOf "USD") >=> entry >=> named "price_amount" >=> castAsInteger ) & limit 10
measureIO $ putPretty $ q >>= (item >=> entry >=> named "acquisition" >=> having (entry >=> named "price_currency_code" >=> asString >=> valueOf "USD") >=> entry >=> named "price_amount" >=> castAsInteger ) & aggregate sum

Decoding

Line separated base 64 encoded gzipped json

while read in; do echo “$in” | base64 –decode | gunzip; echo “”; done < file.lgz > firehose.json

Profiling with stack traces

mafia build -p
cabal repl --ghc-options='-fexternal-interpreter -prof'

import HaskellWorks.Data.Succinct.BalancedParens
import HaskellWorks.Data.Succinct.RankSelect.Binary.Poppy512
import HaskellWorks.Data.Positioning
import qualified Data.Vector.Storable as DVS
import HaskellWorks.Data.IndexedSeq
(jsonBS, jsonIb, jsonBp) <- loadJsonRawWithIndex "firehose.json"
let bp1 = SimpleBalancedParens jsonBp
let bp2 = SimpleBalancedParens (makePoppy512 jsonBp)
let bp3 = makePoppy512 jsonBp

References

• Semi-Indexing Semi-Structured Data in Tiny Space
• Succinct Data Structures talk by Edward Kmett
• Typed Tagless Final Interpreters

Special mentions

• Sydney Paper Club