Improve loadtime by removing LazyArray (and be ready for julia 1.9)

[Moelf]

• Implement support for object caching through pkgimages JuliaLang/julia#47184

#1.8.2
time julia --startup-file=no --project=. -e 'using UnROOT; t = LazyTree(UnROOT.samplefile("tree_with_jagged_array.root"), "t1") |> show'
 30  │ [20, 21, 22, 23, 24, 25, 26, 27, 28]
 31  │ []
  ⋮  │                  ⋮
                             69 rows omitted

________________________________________________________
Executed in    8.80 secs    fish           external
   usr time    8.81 secs    0.00 micros    8.81 secs
   sys time    1.53 secs  631.00 micros    1.53 secs

> time ~/Documents/github/julia/julia --startup-file=no --project=. -e 'using UnROOT; t = LazyTree(UnROOT.samplefile("tree_with_jagged_array.root"), "t1") |> show'
...
 29  │ [20, 21, 22, 23, 24, 25, 26, 27]
 30  │ [20, 21, 22, 23, 24, 25, 26, 27, 28]
 31  │ []
  ⋮  │                  ⋮
                             69 rows omitted

________________________________________________________
Executed in    5.75 secs    fish           external
   usr time    5.82 secs  675.00 micros    5.82 secs
   sys time    1.50 secs    0.00 micros    1.50 secs

[codecov]

Codecov Report

Base: 90.27% // Head: 90.38% // Increases project coverage by +0.11% 🎉

Coverage data is based on head (ee1f8fe) compared to base (f6819e6).
Patch coverage: 80.00% of modified lines in pull request are covered.

❗ Current head ee1f8fe differs from pull request most recent head a50dd83. Consider uploading reports for the commit a50dd83 to get more accurate results

Additional details and impacted files

@@            Coverage Diff             @@
##           master     #189      +/-   ##
==========================================
+ Coverage   90.27%   90.38%   +0.11%     
==========================================
  Files          11       11              
  Lines        1625     1623       -2     
==========================================
  Hits         1467     1467              
+ Misses        158      156       -2     

Impacted Files	Coverage Δ
src/UnROOT.jl	100.00% <ø> (ø)
src/iteration.jl	89.65% <80.00%> (+0.87%)	⬆️

Help us with your feedback. Take ten seconds to tell us how you rate us. Have a feature suggestion? Share it here.

☔ View full report at Codecov.
📢 Do you have feedback about the report comment? Let us know in this issue.

[vchuravy]

What is the timing split between using and doing the task?

[Moelf]

yeah @vchuravy got it, the problem is LazyArray ('s dependency)

julia> @time_imports using UnROOT
      0.9 ms  Statistics
    156.3 ms  FillArrays
      2.2 ms  StaticArraysCore
    571.9 ms  StaticArrays
   1171.1 ms  ArrayLayouts

and adding usage of LazyArray.Vcat in the precompile block doesn't help with this using time, no surprise I guess. We probably should oust it anyway, since we really just need a lazy Vcat of 1D vector

[vchuravy]

Yeah we are not expecting using time to be drastically faster.

[Moelf]

after yeeting the LazyArray:

#1.8.2
  ⋮  │                  ⋮
                             69 rows omitted

________________________________________________________
Executed in    7.19 secs    fish           external
   usr time    7.32 secs    0.00 micros    7.32 secs
   sys time    1.46 secs  515.00 micros    1.46 secs


#1.9 wit the said PR
julia> @time_imports using UnROOT
    543.1 ms  StaticArrays

 29  │ [20, 21, 22, 23, 24, 25, 26, 27]
 30  │ [20, 21, 22, 23, 24, 25, 26, 27, 28]
 31  │ []
  ⋮  │                  ⋮
                             69 rows omitted

________________________________________________________
Executed in    4.05 secs    fish           external
   usr time    4.26 secs   11.66 millis    4.25 secs
   sys time    1.43 secs    3.16 millis    1.42 secs

[giordano]

This should help for any version of julia, no? Also, top-level @static does nothing: top-level expressions in a package are evaluated at compile-time anyway.

[Moelf]

this doesn't help for <1.9

[Moelf]

got even faster after JuliaLang/julia#47184

> time ~/Documents/github/julia/julia --startup-file=no --project=. -e 'using UnROOT; t = LazyTree(UnROOT.samplefile("tree_with_jagged_array.root"), "t1") |> show'
 Row │ int32_array
     │ SubArray{Int32,
─────┼──────────────────────────────────────
 1   │ []
 2   │ [0]
                             69 rows omitted

________________________________________________________
Executed in    2.61 secs    fish           external
   usr time    2.52 secs  638.00 micros    2.52 secs
   sys time    0.09 secs    0.00 micros    0.09 secs