Under 2 minutes, could probably start optimizing as I did for rust, but it's good enough for now

src/main/julia/main.jl

@@ -33,23 +33,31 @@ function print_measurements(stations::Dict{String,StationMeasurements})
     print("}")
 end
 
-function main()
+function merge(stations_vec::Vector{Dict{String,StationMeasurements}})
-    open("../../../measurements.txt", "r") do f
+    merged = Dict{String,StationMeasurements}()
-        println("Start")
+    for stations in stations_vec
-        sz = Base.stat(f).size
+        for (city, sm) in stations
-        data = mmap(f, Vector{UInt8}, sz)
+            if haskey(merged, city)
-        idxs = findall(isequal(0x0a), data)
+                merged_sm = merged[city]
-        stations = Dict{String,StationMeasurements}()
+                sm.min = ifelse(merged_sm.min < sm.min, merged_sm.min, sm.min)
-        iteration = 0
+                sm.max = ifelse(merged_sm.max > sm.max, merged_sm.max, sm.max)
-        last_idx = 1
+                sm.sum += merged_sm.sum
-        for i in eachindex(idxs)
+                sm.count += merged_sm.count
-            if iteration % 1000000 == 0 && iteration > 0
+            else
-                print("\x1b[J\x1b[H")
+                merged[city] = sm
-                percent = round((iteration / 1000000000) * 100; digits=2)
-                println("$(percent)%")
             end
-            line = String(data[last_idx:idxs[i]-1])
+        end
-            last_idx = idxs[i] + 1
+    end
+    merged
+end
+
+function process_chunk(data, chunk)
+    stations = Dict{String,StationMeasurements}()
+    for i in eachindex(chunk)
+        if i == 1
+            continue
+        end
+        line = String(data[chunk[i-1]:chunk[i]-1])
         station, temp_str = rsplit(line, ";")
         temp = parse(Float32, temp_str)
         if haskey(stations, station)
@@ -61,10 +69,22 @@ function main()
         else
             stations[station] = StationMeasurements(temp, temp, temp, 1)
         end
-            iteration += 1
     end
+    stations
+end
+
+function main()
+    open("../../../measurements.txt", "r") do f
+        sz = Base.stat(f).size
+        data = mmap(f, Vector{UInt8}, sz)
+        idxs = findall(isequal(0x0a), data)
+        idxs_chunks = collect(Iterators.partition(idxs, length(idxs) ÷ Threads.nthreads()))
+        tasks = map(idxs_chunks) do chunk
+            Threads.@spawn process_chunk(data, chunk)
+        end
+        stations_vec = fetch.(tasks)
+        stations = merge(stations_vec)
         print_measurements(stations)
-        println("End")
     end
 end