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Readme for analog3.0

Analog's Definitions

This page describes how analog defines its terms, and exactly what is counted in each category. We start with some basic definitions.

The host is the computer which has asked you for a file. The file might be a page (i.e., an HTML document) or it might be something else, such as an image. The total requests counts all the files which have been requested, including pages, graphics, etc. (Some people call this the number of hits, but that word is used in different ways by different people, so I avoid it). The requests for pages obviously only counts pages. The referrer for a request is the place that the user (or his computer) heard about your file from. If he followed a link to reach a page, it will be the previous page. In the case of a graphic on a page, the referrer will be the page containing the graphic.

Analog recognises four categories of request, based on the HTTP status code of the request. You can see the total number of requests for each status code, and what the codes mean, in the Status Code Report. (Or see the HTTP spec for a detailed description.)

First, successful requests are those with HTTP status codes in the 200's (where the document was returned) or with code 304 (where the document was requested but was not needed because it had not been recently modified and the user could use a cached copy). Sometimes the logfile line doesn't contain a status code. These lines are also assumed by analog to be successes.

Redirected requests are those with other codes in the 300's, indicating that the user was directed to a different file instead. The most common cause of these requests is that the user has incorrectly requested a directory name without the trailing slash. The server replies with a redirection ("you probably mean the following") and the user then makes a second connection to get the correct document (although usually the browser does it automatically without the user's intervention or knowledge). The other common cause of redirected requests is their use as "click-thru" advertising banners.

Failed requests are those with codes in the 400's (error in request) or 500's (server error). They come about for a variety of reasons, but the most common are when the requested file is not found or is read-protected.

Finally, requests returning informational status code are those with status codes in the 100's. These are very rare at the moment.

There are a few other types of logfile lines listed in the General Summary. Lines without status code refers to those logfile lines without a status code, and the successful requests in the General Summary only counts the ones with a status code: except if the line contains the name of the file requested, and the filename is being counted (not starred in the LOGFORMAT), then it's listed in the successes. Corrupt logfile lines are those which analog didn't manage to parse. And unwanted logfile entries are ones which we have specifically excluded. Successful requests for pages refers to those lines on which the file requested was given and was defined as a page by the PAGEINCLUDE command.

Most reports only include successful requests in calculating the number of requests, requests for pages, bytes, and last date: unless, of course, the report is a redirection or failure report. There is a further restriction on the time reports, the status code report and the file size report: the logfile line must also contain the name of the file requested, and the filename must be being counted. This is necessary to stop double counting if the server uses separate logs.

The "not listed" line at the bottom of each of the non-time reports includes both those items which were explicitly excluded at the output stage with an OUTPUTEXCLUDE command, and those which were not listed because they were below the floor for the report.

The figures in parentheses in the General Summary are for the last seven days: either the seven days before the TO time, or if no TO time is given, the seven days before the time of the program start. (It would be nicer to use the seven days before the last time in the logfile, but we don't know when this is until we've read the whole logfile, and by then it's too late.) The figures for the last seven days are not included if all, or none, of the requests fall in the last seven days.

In the Domain Report, "domain not given" means that the hostname did not contain a dot. "Unknown domain" means that it did contain a dot, but that the domain name was not in the domains file.

There are probably some other things which I could include on this page. If you have any suggestions, then feel free to contact me. Next I shall give an explanation of all the errors and warnings which analog can generate.
Stephen Turner
E-mail: sret1@cam.ac.uk

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