Haxl.Core.Stats

Types and operations for statistics and profiling. Most users should import Haxl.Core instead of importing this module directly.

Data-source stats

newtype Stats

Stats that we collect along the way.

Constructors

Stats [FetchStats]

Instances

Show Stats

Methods

showsPrec :: Int -> Stats -> ShowS

show :: Stats -> String

showList :: [Stats] -> ShowS

Semigroup Stats

Methods

(<>) :: Stats -> Stats -> Stats

sconcat :: NonEmpty Stats -> Stats

stimes :: Integral b => b -> Stats -> Stats

Monoid Stats

Methods

mempty :: Stats

mappend :: Stats -> Stats -> Stats

mconcat :: [Stats] -> Stats

ToJSON Stats

Methods

toJSON :: Stats -> Value

toEncoding :: Stats -> Encoding

toJSONList :: [Stats] -> Value

toEncodingList :: [Stats] -> Encoding

data FetchStats

Maps data source name to the number of requests made in that round. The map only contains entries for sources that made requests in that round.

Constructors

FetchStats

Timing stats for a (batched) data fetch

Fields

• fetchDataSource :: Text
• fetchBatchSize :: !Int
• fetchStart :: !Timestamp
• fetchDuration :: !Microseconds
• fetchSpace :: !Int64
• fetchFailures :: !Int

FetchCall

The stack trace of a call to dataFetch. These are collected only when profiling and reportLevel is 5 or greater.

Fields

• fetchReq :: String
• fetchStack :: [String]

Instances

Show FetchStats

Methods

showsPrec :: Int -> FetchStats -> ShowS

show :: FetchStats -> String

showList :: [FetchStats] -> ShowS

ToJSON FetchStats

Methods

toJSON :: FetchStats -> Value

toEncoding :: FetchStats -> Encoding

toJSONList :: [FetchStats] -> Value

toEncodingList :: [FetchStats] -> Encoding

type Microseconds = Int64

type Timestamp = Microseconds

getTimestamp :: IO Timestamp

emptyStats :: Stats

numRounds :: Stats -> Int

numFetches :: Stats -> Int

ppStats :: Stats -> String

Pretty-print Stats.

ppFetchStats :: FetchStats -> String

Pretty-print RoundStats.

Profiling

data Profile

emptyProfile :: Profile

profile :: Profile -> HashMap ProfileLabel ProfileData

Data on individual labels.

type ProfileLabel = Text

data ProfileData

Constructors

ProfileData

Fields

• profileAllocs :: !AllocCount

  allocations made by this label

• profileDeps :: HashSet ProfileLabel

  labels that this label depends on

• profileFetches :: HashMap Text Int

  map from datasource name => fetch count

• profileMemoHits :: !MemoHitCount

  number of hits to memoized computation at this label

Instances

Show ProfileData

Methods

showsPrec :: Int -> ProfileData -> ShowS

show :: ProfileData -> String

showList :: [ProfileData] -> ShowS

emptyProfileData :: ProfileData

type AllocCount = Int64

type MemoHitCount = Int64

Allocation

getAllocationCounter :: IO Int64

Return the current value of the allocation counter for the current thread.

Since: 4.8.0.0

setAllocationCounter :: Int64 -> IO ()

Every thread has an allocation counter that tracks how much memory has been allocated by the thread. The counter is initialized to zero, and setAllocationCounter sets the current value. The allocation counter counts *down*, so in the absence of a call to setAllocationCounter its value is the negation of the number of bytes of memory allocated by the thread.

There are two things that you can do with this counter:

• Use it as a simple profiling mechanism, with getAllocationCounter.
• Use it as a resource limit. See enableAllocationLimit.

Allocation accounting is accurate only to about 4Kbytes.

Since: 4.8.0.0