The following table summarizes the meaning of all terms in the
statistics report which are not self-explaining:

Hits: A hit is any response from the
server on behalf of a request sent from a browser. This includes any
response from the server, not only text files or documents. If, for
example, a HTML page has two images embedded, the server generates
three hits if this page is requested: one hit for the HTML page itself
and two hits for the two inline images.

Files: If the user requests a document and the
server successfully sends back a file for this request, this is
counted as a Code 200 (OK) response. Any such response is
counted for as a file. Again, "file" here means any kind of
a file.

Code 304: A Code 304 (Not Modified) response
is generated by the server if a document hasn't been updated since the
last time it was requested by the user and therefore there was no need
to actually send the files for this document. This happens if the
browser (or a caching proxy server between the browser and your web
server) still has an up-to-date copy of the page in it's local storage
(cache) and therefore can display the page without requesting the
actual content. This technique is used to reduce network traffic, but
it also causes an inaccuracy in the statistics reports regarding the
number of visitors, because the browser or proxy usually sends only
one such a conditional request per user session if it still holds an
up-to-date copy of the file. However, the ratio between files
and 304's reflects the efficiency of overall caching mechanisms
for at least those hits which made it's way to the server.

Pageviews: Pageviews are all files which either have
a text file suffix (.html, .text) or which are directory
index files. This number allows to estimate the number of
"real" documents transmitted by your server. If defined
correctly, the analyzer rates text files (documents) as pageviews.
Those pageviews do not include images, CGI scripts, Java applets or
any other HTML objects except all files ending with one of the
pre-defined pageview suffixes, such as .html or .text.
See also the PageView directive in the section Configuration
File in the manpage.

Other responses: There are much more responses than only Code
200 (OK) and Code 304 (Not Modified) responses, especially
in the coming standard, the HTTP 1.1 protocol specification. For
example, the server could generate a Code 302 (Redirected)
response if a page has moved, a Code 401 (Unauthorized Request)
response if access to the document is denied or a Code 404 (Not
Found) response if the requested page does not exist on this
server. See the HTML
specification for information about all valid responses from a web
server. Note that http-analyze does recognize HTTP/1.1
responses according to RFC2068.

KBytes transferred: This is the amount of data sent during
the whole summary period as reported by the server. Note that some
servers log the size of a document instead of the actual number of
bytes transferred. While in most cases this is the same, if a user
interrupts the transmission by pressing the browser's stop button
before the page has been received completely, some servers (for
example all Netscape web servers) do not log the amount of data
transferred but the amount of data which would have been transferred
if the user would have completely loaded the page.

KBytes requested: This is the amount of data requested
during the whole summary period. http-analyze computes this
number by summing up the values of KBytes transferred and KBytes
saved by cache (see below).

KBytes saved by cache: The amount of data saved by various
caching mechanisms such as in proxy servers or in browsers. This value
is computed by multiplying the number of Code 304 (Not Modified)
requests per file with the size of the corresponding file. Note:
Because http-analyze can determine the size of a file only if
the file has been requested at least once in the same summary period,
the values for KBytes saved by cache and KBytes requested are
just approximations of the real values.

Unique URLs: Unique URLs
are the number of all different, valid URLs requested in a given
summary period. This shows you the number of all different files
requested at least once in the corresponding summary period.

Unique sites: This is the sum of all unique hosts
accessing the server during a given time-window . The time-window is
hardwired to the length of the current month. This means that if a
host accesses your server very often, it gets counted only once during
the whole month. Only the sum of the unique hosts per month is listed
in the statistics report.

Sessions: Similar to unique sites, this is
the number of unique hosts accessing the server during a given
time-window. This time-window is one day by default for backward
compatibility, but it can be changed with the option -u or the Session
directive in the configuration file. For example, if the time-window
is two hours, all accesses from a certain host in less than 2 hours
after the first access from this host are lumped together into one
session. All following accesses more than 2 hours apart from the first
access will be counted as a new session. This way you may get an
estimated number of how many sessions are started on different sites
to access your server.