- Limited upload speed of server's internet connection (in my case, about 1 Mbps)
- Quantity of transmitted data
If I didn't screw up the implementation and I interpreted my debug messages correctly, without compression the total data transmitted by the server would have been 7.2 GB with the largest message data size (toward the end of the run) being 13.2 MB. With compression this was reduced to 1.4 GB and 2.4 MB; uncompressed message sizes of 2.4 MB would have started showing about at around 2.5 minutes.
I have since rebased my quick-and-dirty branch off of master (see my msg_data_compression branch on GitHub.) EDIT: The test used the max compression option for zlib. I removed that from the current version; I don't know how to judge the trade-offs involved.
Is there any interest in having something like this merged into FreeOrion?