function _update_left_with_right!(x, y, ranges, allowmissing, mode::F; threads = true, op = nothing) where F

if op === nothing

@_threadsfor threads for i in 1:length(x)

if length(ranges[i]) > 0

if mode(x[i])

if !allowmissing && !ismissing(y[ranges[i].stop])

x[i] = y[ranges[i].stop]

elseif allowmissing

x[i] = y[ranges[i].stop]

end

end

end

end

else

@_threadsfor threads for i in 1:length(x)

if length(ranges[i]) > 0

if mode(x[i])

if !allowmissing && !ismissing(y[ranges[i].stop])

x[i] = op(x[i], y[ranges[i].stop])

elseif allowmissing

x[i] = op(x[i], y[ranges[i].stop])

end

end

end

end

end

end

function _update!(dsl::Dataset, dsr::AbstractDataset, ::Val{T}; onleft, onright, check = true, allowmissing = true, mode = :all, mapformats = [true, true], stable = false, alg = HeapSort, accelerate = false, usehash = true, method = :sort, threads = true, op = nothing) where T

isempty(dsl) && return dsl

if method == :hash

ranges, a, idx, minval, reps, sz, right_cols = _find_ranges_for_join_using_hash(dsl, dsr, onleft, onright, mapformats, true, Val(T); threads = threads)

elseif method == :sort

oncols_left = onleft

oncols_right = onright

right_cols = setdiff(1:length(index(dsr)), oncols_right)

ranges = Vector{UnitRange{T}}(undef, nrow(dsl))

if usehash && length(oncols_left) == 1 && nrow(dsr)>1

success, result = _update!_dict(dsl, dsr, ranges, oncols_left, oncols_right, right_cols, Val(T); mapformats = mapformats, allowmissing = allowmissing, mode = mode, threads = threads, op = op)

if success

return result

end

end

idx, uniquemode = _find_permute_and_fill_range_for_join!(ranges, dsr, dsl, oncols_right, oncols_left, stable, alg, mapformats, accelerate, threads = threads)

for j in 1:length(oncols_left)

_change_refpool_find_range_for_join!(ranges, dsl, dsr, idx, oncols_left, oncols_right, mapformats[1], mapformats[2], j, threads = threads)

end

end

if mode == :all

f_mode = x->true

elseif mode == :missing || mode == :missings

f_mode = x->ismissing(x)

else

f_mode = x->mode(x)::Bool

end

for j in 1:length(right_cols)

if haskey(index(dsl).lookup, _names(dsr)[right_cols[j]])

left_cols_idx = index(dsl)[_names(dsr)[right_cols[j]]]

TL = nonmissingtype(eltype(_columns(dsl)[left_cols_idx]))

TR = nonmissingtype(eltype(_columns(dsr)[right_cols[j]]))

if promote_type(TR, TL) <: TL

_update_left_with_right!(_columns(dsl)[left_cols_idx], view(_columns(dsr)[right_cols[j]], idx), ranges, allowmissing, f_mode, threads = threads, op = op)

end

end

end

_modified(_attributes(dsl))

dsl

end