some cleanup

Author: sl-solution

src/sort/gatherby.jl

@@ -115,8 +115,6 @@ function compute_indices(groups, ngroups, ::Val{T}; threads = true) where T
 	idx, starts
 end
 
-# fast combine for gatherby data
-
 mutable struct GatherBy
     parent
     groupcols
@@ -208,29 +206,14 @@ function gatherby(ds::AbstractDataset, cols::MultiColumnIndex; mapformats::Bool
 end
 gatherby(ds::AbstractDataset, col::ColumnIndex; mapformats = true, stable = true, isgathered = false, eachrow = false, threads = true) = gatherby(ds, [col], mapformats = mapformats, stable = stable, isgathered = isgathered, eachrow = eachrow, threads = threads)
 
-
-__SPFRMT(x) = x & 1023
-__SPFRMT(::Missing) = missing # not needed
-
-# currently not been used in gatherby
-# use sort and format trick for fast gatherby - hm stands for high memory footprint
-function hm_gatherby(ds::AbstractDataset, cols::MultiColumnIndex; mapformats = false, threads = true)
-	modify!(ds, cols=>byrow(hash; threads = threads, mapformats = mapformats)=>:___tmp___cols8934, :___tmp___cols8934=>identity=>:___tmp___cols8934_2)
-	setformat!(ds, :___tmp___cols8934_2=>__SPFRMT)
-	gds = groupby(ds, [:___tmp___cols8934_2, :___tmp___cols8934], stable = false, threads = threads)
-	grpcols, ranges, last_valid_index = _find_starts_of_groups(view(ds, gds.perm, cols), cols, nrow(ds) < typemax(Int32) ? Val(Int32) : Val(Int64); mapformats = mapformats, threads = threads)
-	select!(ds, Not([:___tmp___cols8934, :___tmp___cols8934_2]))
-	GatherBy(ds, grpcols, nothing, last_valid_index, mapformats, gds.perm, ranges, _get_lastmodified(_attributes(ds)))
-end
-
 function _fill_mapreduce_col!(x, f, op, y, loc)
     @inbounds for i in 1:length(y)
         x[loc[i]] = op(x[loc[i]], f(y[i]))
     end
 end
 
 # only for calculating var - mval is a vector of means
-function _fill_mapreduce_col!(x, mval::Vector, op, y, loc)
+function _fill_mapreduce_col!(x, mval::AbstractVector, op, y, loc)
 	@inbounds for i in 1:length(y)
         x[loc[i]] = op(x[loc[i]], _abs2mean(y[i], mval[loc[i]]))
     end
@@ -249,7 +232,7 @@ function _fill_mapreduce_col_threaded!(x, f, op, y, loc, nt)
 end
 
 # only for calculating var - mval is a vector of means
-function _fill_mapreduce_col_threaded!(x, mval::Vector, op, y, loc, nt)
+function _fill_mapreduce_col_threaded!(x, mval::AbstractVector, op, y, loc, nt)
 	@sync for thid in 0:nt-1
 		Threads.@spawn for i in 1:length(y)
         	@inbounds if loc[i] % nt == thid
@@ -383,7 +366,7 @@ const FAST_GATHERBY_REDUCTION = [sum, length, minimum, maximum, mean, var, std,
 
 function _fast_gatherby_reduction(gds, ms)
     !(gds isa GatherBy) && return false
-    gds.groups == nothing && return false
+    gds.groups === nothing && return false
     for i in 1:length(ms)
         if (ms[i].second.first isa Expr) && ms[i].second.first.head == :BYROW
         elseif (ms[i].second.first isa Base.Callable)