Differences to Note When Migrating Between Urchin Products
This document is an overview describing basic differences in data analysis as well as certain migration issues when moving from one major Urchin version to another. Each major Urchin version is listed along with a summary explaining key elements of how data is analyzed. The latter portion of this page covers issues to anticipate for particular migration scenarios.
Urchin 3
- Visitor tracking is done by incoming IP address only. There is no distinction between a visitor and a session.
- All MIME types except images (gif/jpg/png) are treated as pageviews.
- Pageview hits with a HEAD request type are logged as treated as actual pageviews.
- Pageviews are not required to count a visitor, so a request for a single image file could be counted as a new visitor.
- Hits with error codes of 404 or 5xx are considered legitimate visits and could increment the visitor count.
- Traffic->Hourly report and Tracking reports (e.g. Top Entrances, Top Exits) data is stored on a monthly basis, therefore the only report granularity is for a single month date range.
Urchin 4
- The default visitor tracking method uses a combination of IP address plus the User-Agent field from log entries. Other tracking options include UTM-1, session id, and IP-only (i.e. Urchin 3 style tracking).
- Urchin 4 provides UTM-1 to enable optimal visitor and session tracking. UTM-1 utilizes client side cookies to identify unique individuals as opposed to relying on IP addresses, which are not necessarily unique to a particular person or system.
- By default a session requires a legitimate pageview to be counted. A request for an image is not considered a pageview nor is a request with a status code other than 2xx, 302, or 304. This will typically reduce counts for visitors, sessions, pageviews and related reports in Urchin 4 using IP-Only tracking when compared to Urchin 3 reports for the same data. The pageview requirement is configurable by the Urchin administrator for sites that have a design that makes counting of images as pageviews desirable.
- When using UTM-1 tracking, sessions without UTM cookie info will be processed using the default of IP+User-Agent.
- Traffic->Hourly report and Tracking reports (e.g. Top Entrances, Top Exits) data is stored on a daily basis, therefore the report granularity is for any time period of a day or greater.
Urchin 5
- The default visitor tracking method uses a combination of IP address plus the User-Agent field from log entries. Other tracking options include UTM (either UTM-2 or UTM-1), session id, username, and IP-only (i.e. Urchin 3 style tracking).
- Urchin 5 provides improved visitor and session tracking based on UTM-2, which uses client side cookies with a configurable session timeout. With this technology, hits with the same cookies spread out over a large period of time can be counted as multiple sessions as opposed to a single long session. This produces more meaningful averages in the reports.
- For both UTM-1 and UTM-2 tracking, the processing logic has changed so that only hits with UTM cookie information are processed when counting visitors, sessions, and pageviews. Hits without UTM info do not fall back to processing using IP+UserAgent as in Urchin 4. Such non-cookie sessions are tracked only for reports that are based on hits and bytes. This can lower counts for visitors, sessions, pageviews, and related reports when compared to Urchin 4 because it significantly reduces the effect of robot traffic on your statistics.
- An explicit include or exclude MIME type list is now used to define what
a pageview is. By default, Urchin 5 excludes the following MIME types
from the pageview list: gif,jpg,jpeg,png,js,css,cur,ico,ida
All other MIME types are considered to be pageviews or downloads. - Pageview hits which use HEAD as the request type only cause the Hits count for that page to be incremented, the pageview count is not.
- By default a session requires a legitimate pageview to be counted. A request for an image is not considered a pageview nor is a request with a status code other than 2xx, 302, or 304. This will typically reduce counts for visitors, sessions, pageviews and related reports in Urchin 5 using IP-Only tracking when compared with older Urchin version reports for the same data. The pageview requirement is configurable by the Urchin administrator for sites that have a design that makes counting of images as pageviews desirable.
- With the exception of the Status and Errors report, all reports that graph vs. hits are based on valid hits. Previously, such graphs were based on all hits (i.e. valid and hits with errors).
- Traffic->Hourly report and Tracking reports (e.g. Top Entrances, Top Exits) data is stored on a daily basis, therefore the report report granularity is for any time period of a day or greater.
Migrating from Urchin 3 to Urchin 5
Reporting
Since in Urchin 3 the Tracking reports and Traffic->Hourly Graph data is only stored on a monthly basis, and in Urchin 4 and Urchin 5 this data is stored on a daily basis, a side by side comparison of these reports requires that you set the date range to one month in the newer products. Also, when importing Urchin 3 data there is no way to break out the monthly data for these reports into individual days, so all data for these specific reports for a given month will be placed into the first day of the month in the newer Urchin version. Here too, setting the date range to one month will allow the imported historical data to be viewed in the correct context.
Administration
Administration is primarily via graphical interface and is based on a binary configuration database. However, command line tools and the ability to import a flat file configuration are available for those who are used to and prefer the config file approach of Urchin 3.
Migrating from Urchin 4 to Urchin 5
Reporting
Urchin 4 databases are fully compatible with Urchin 5. Report data will be immediately available once you upgrade. As noted above in the product descriptions, Urchin 5 uses a different logic for processing hits, so once you upgrade you will initially see a difference in report numbers compared to recent historical data generated with Urchin 4. These variances will differ depending on which visitor tracking method you've been using.
Log Tracking
Logtracking data in Urchin 4 is kept in a single tracking file. In Urchin 5 this data is kept in individual monthly databases. When an Urchin 4 installation is upgraded to Urchin 5, the old logtracking data is converted into equivalent Urchin 5 monthly logtracking databases, and the Urchin 4 logtrack file is archived.
Migrating from UTM-1 to UTM-2
Reporting
IMPORTANT: UTM-2 cannot be used with Urchin 4. You must be running Urchin 5 before switching your website to use UTM-2.
The improved accuracy in identifying unique visitors that UTM-2 provides means that you may see some differences in reported numbers compared to what you have been seeing using UTM-1. These differences should be on the order of 10% or less.