As the tests on the more powerful server didn’t show a dramatic increase of performances, we decided to stay with our existing server. After the addition of an index by David recently, I’ve done a few tests on rendering duration in different conditions :
- On the France-only database (our “production” database)
- On the France-only database, with the daily diff being applied on another database
- On the world database (our “development database”)
- On the world database, with the daily diff being applied to this database
For each case, I’ve done the rendering of three different french cities (Rennes, Colomiers and Sanguinet) in PDF, PNG and SVGZ formats, and I’ve done each test twice.
Rennes
- World-database, without daily udate process: 2 minutes 5 seconds, 1 minute 51 seconds
- World database, with daily update process: 3 minutes 3 seconds, 2 minutes 10 seconds
- France-only database, without daily update process: 1 minute 48 seconds, 1 minute 47 seconds
- France-only database, with daily update process on the world database: 3 minutes 54 seconds, 2 minutes 25 seconds
Colomiers
- World-database, without daily udate process: 37 seconds, 32 seconds
- World database, with daily update process: 1 minutes 5 seconds, 39 seconds
- France database, without daily update process: 31 seconds, 31 seconds
- France database, with daily update process on the world database: 51 seconds, 37 seconds
Sanguinet
- World-database, without daily udate process: 33 seconds, 39 seconds
- World database, with daily update process: 49 seconds, 56 seconds
- France database, without daily update process: 32 seconds, 36 seconds
- France database, with daily update process on the world database: 42 seconds, 40 seconds
Conclusions
First, we can conclude that when the daily update process is not running, the rendering time for a given city is only slightly longer on the world database than on the France-only database. So, the index added by David is very efficient and solved our main issue.
Secondly, when the daily update process is running, the rendering time increases up to 50% in the worst cases. It’s a lot, but the daily update process is very I/O intensive so we expected a large impact on the rendering time. However, the rendering times remain acceptable, since the rendering is done asynchronously on MapOSMatic.org.
Therefore, I think we will soon put into production the world database, which will be updated every day with the OpenStreetMap data.
Funnily, the main title of the magazine was about the supposedly wonderful new features of Windows Seven. Something most OpenStreetMap contributors probably don’t care about 