Troubleshoot map service performance with server logs

Fine-grained logging down to the layer draw level is available through the logging level Verbose. The detailed logging is helpful when troubleshooting performance issues. In this topic, consider the scenario that you have a map service that's not drawing quickly enough.

When you need more detail about what's happening during a map draw, you can go to the Logs module in ArcGIS Server Manager, enable logging at the Verbose level, make a request to the map service, and view the resulting log. To do so, complete the following steps:

1. Open Manager and log in. If you need help with this step, see Log in to Manager.
2. Click Logs > View Logs > Settings.
3. Set the log level to Verbose and click Save.
4. In a client application, make a simple request to your map service by panning or zooming. Note the current time so you can pinpoint the request in the log.
5. In Manager, click Logs > View Logs.
6. In the log Level drop-down list, choose Verbose.
7. In the Source drop-down list, choose your map service.

   It's listed as ServiceName.MapServer.

8. Click Query.
9. Examine the log that was created during your request and note the feature count and elapsed draw time of each layer. It may be helpful to print the log and use a highlighter pen to note the draw times. To do this, click Printer Friendly View in the View Logs module. You'll immediately see which layers are taking the longest to draw. Also, review the feature count to spot inefficient layers. A layer may take only 0.2 seconds to draw at a particular extent, but if the extent only includes two features, you may have a potential inefficiency.
10. Repeat this process at several locations and scales in your map.

    You want to analyze a good sample of the symbology and layers in your map.

11. When you finish, set the log level back to Warning.

The Map service log codes topic contains a table of the codes you'll see when analyzing the detailed logging. If you scroll down the topic, you'll also find an example of the codes returned from an ExportMapImage request like the one that occurs when you pan or zoom the map.

When examining detailed logs, you'll often see the messages Beginning of layer draw and End of layer draw. The time between the beginning and the end of the layer draw is the time the request spends in the GIS server tier. If you determine that performance is acceptable in the GIS server tier but your application is still slow, it's possible that your web server is the cause or that your application is waiting for available service instances so it can draw the layer.

To learn more about troubleshooting the server with logs, see Server logs.