Download status shows deceptive data size

[gaben]

What steps will reproduce the problem?

1. Download a bigger dataset from the OSM or overpass server (the default XML option is fine)
2. Look at the download status indicator, especially the data size
3. Save the file as .osm
4. Compare the file size to what the window showed

What is the expected result?

The data size indicator should show more realistic or true data size.

What happens instead?

It shows something else. In this case a moment before disappearing around 24MB. But the saved .osm file is nearly 300MB.

Please provide any additional information below. Attach a screenshot if possible.

URL:https://josm.openstreetmap.de/svn/trunk
Repository:UUID: 0c6e7542-c601-0410-84e7-c038aed88b3b
Last:Changed Date: 2020-01-04 20:16:33 +0100 (Sat, 04 Jan 2020)
Build-Date:2020-01-05 02:30:56
Revision:15632
Relative:URL: ^/trunk

Identification: JOSM/1.5 (15632 en) Windows 10 64-Bit
OS Build number: Windows 10 Pro 1909 (18363)
Memory Usage: 1034 MB / 1820 MB (484 MB allocated, but free)
Java version: 1.8.0_231-b11, Oracle Corporation, Java HotSpot(TM) 64-Bit Server VM
Screen: \Display0 1920x1200
Maximum Screen Size: 1920x1200
VM arguments: [-Djava.security.manager, -Djava.security.policy=file:<java.home>\lib\security\javaws.policy, -DtrustProxy=true, -Djnlpx.home=<java.home>\bin, -Djnlpx.origFilenameArg=%UserProfile%\AppData\LocalLow\Sun\Java\Deployment\cache\6.0\31\583aa85f-117c60e1, -Djnlpx.remove=false, -Djava.util.Arrays.useLegacyMergeSort=true, -Djnlpx.heapsize=NULL,2048m, -Djnlpx.splashport=64939, -Djnlp.application.href=https://josm.openstreetmap.de/download/josm-latest.jnlp, -Djnlpx.jvm=<java.home>\bin\javaw.exe]

[GerdP]

I think when you download the data is gzip compressed. So, if you save it as uncompressed file the size must be bigger.

[gaben]

If it uses compression the string maybe can be reworded to something like this "Downloading compressed data...". What do you think?

[stoecker]

Replying to gaben:

If it uses compression the string maybe can be reworded to something like this "Downloading compressed data...". What do you think?

No. That's simply the way HTTP works. Data may or may not be transferred compressed based on the abilities of the client and the settings on the server. As this is no download dialog showing the final data size, but rather a progress bar showing the progress of the download there is no reason to change anything.

Anyway the downloaded size and the saved file will never match. Although it is similar it is not the same file format.

[gaben]

Forget everything, the issue description and the comments as well.

Imagine the following. As a user, you are downloading some data the download indicator shows about 25MB. It's not much and you have a decent computer, but the program (eg. JOSM) is still lagging. Why?

[GerdP]

Because 25 MB of compressed OSM data requires a lot more heap memory in JOSM. You probably have to increase the java run time parameter to a value higher than 2GB, e.g. -Xmx4G.