francis picabia <fpicabia@gmail.com> writes:
> The server was running Moodle. The slow load time was noticed when loading
> a quiz containing
> multiple images. All Apache log results showed a 6 seconds or a multiple
> of 6 for how long
> it took to retrieve each image.
> Interestingly, if I did a wget, on the server, to the image link (which was
> processed through a pluginfile.php URL)
> even the HTML page returned of "please login first" took consistently 6
> seconds. Never 2, 3, 4, 5 or 7, 8, 9...
> So whatever was wrong, there was a 6 second penalty for this.
Hmm ... some weird DNS behavior, perhaps? That is one way to explain
a pattern like this. How long does it take to "dig" or "nslookup"
your server name?
regards, tom lane
Nope, it isn't DNS related. The dev server uses same DNS service and
was very fast to do the same actions. I also run the DNS server and would be aware
of any complaints about the performance. I thought firewall for awhile but there was
nothing there related to it.
It all cleared up minutes after the vacuum -a -v -z was run,
and was reported slow several days before this. I myself saw it consistently slow
for the quiz for the 2.5 days I fought the problem. We're certain the vacuum
made the difference in performance.
If there is no way to log the "user time", I guess we'd need to log something
like the connection and disconnection to get another idea on the time elapsing.