Bug Reporting II

The address of the site is "", not "". Seems to work fine for me using the site's proper address.

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--	Percy
	EvC Forum Director

I wish I could explain why accessing the site with "" works, but I can't. I'm sure others can.However, one thing I can tell you is that if you begin accessing the site using "", then all links on that page will be "". This is because every page is dynamically constructed on the fly when you click on a link, and the top-level address of the site is filled in using the address that you used to access it.

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--	Percy
	EvC Forum Director

If you're saying that you found an "" link on a "" webpage, then that shouldn't be possible. If you're actually seeing this, can you provide enough information for me to reproduce it myself?Edited by Admin, : Change author to Admin.

Today's problems in the Coffee House forum should be resolved, but they will recur in various forums from time to time. The search database file for a forum can only grow so large before it takes longer to update than the timeout for browser windows. When a forum's search database grows larger than around 30 MB then we have to clear the search database for that forum. New posts are logged as they are posted and so are searchable, but the logging of old posts is lost and so they are not searchable.This problem will be resolved when threads move into the database sometime next year.

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--	Percy
	EvC Forum Director

The computer help thread experienced a data loss, and its internal index no longer accurately reflects the messages, which causes the page links to not work accurately. I may be able to fix this by making the index agree with the messages that actually remain.The "unread messages" indicator stops working when you've accessed the site with both "" (recommended) and "" (not recommended). This is a bug that I will eventually fix. In the meantime, if you find yourself affected by this just delete cookies for EvC Forum and all will be well (you'll have to log in again, of course).Internet Explorer cannot delete cookies for individual sites, but those of you who know your way around the Cookies directory can find the one for "" and delete it. This has the advantage of leaving the "" cookie intact, so you do not have to log in again.

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--	Percy
	EvC Forum Director

Yep, exactly. Some members tend to leave the leading "www" off the links they post.I'm going to try to fix the computer help thread now. Temporarily closing it.

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--	Percy
	EvC Forum Director

What bug?Happy New Year everyone!

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--	Percy
	EvC Forum Director

Problem fixed, thanks for letting us know!

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--	Percy
	EvC Forum Director

The search database for Coffee House overflowed, bogging everything down as processes backed up. I reset the database, and now searches in the Coffee House forum for posts prior to last night will not be found, but of course Google indexes this site frequently.

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--	Percy
	EvC Forum Director

Either the entire membership of the "My Birthday is March 28, 1983" club joined, or the database was somehow corrupted and caused 293 members to have their date of birth set to 3/28/1983. I've set the birthday for these members back to the null default, so if you were actually born this upcoming Wednesday 24 years ago, you'll have to go to your profile and set your date of birth back to March 28, 1983.

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--	Percy
	EvC Forum Director

Our server is subject to periodic attacks by spammers who co-opt the server by dumping huge numbers of spam emails into the spam queue. I don't know how to prevent this, and our web hosting company feels no responsibility to provide protection and wants $150/hour to fix it.When such attacks occur, the server slows to a crawl because it begins a new process for each spam email, and with over a thousand processes vying for the processor's attention, thrashing causes most of the processor's cycles to be devoted to switching from one process to the next.With such frequent context switching, the likelihood increases of stumbling across holes in the semaphore protection that prevents process interruption during critical activities, such as assigning the next message number. It also makes it more likely to run into timeouts that kill a process after a fixed number of seconds, which is what causes the "Online now" list to occasionally get corrupted.Moving to our own server has been both a curse and a boon. The downside issues are few, but this one is particularly severe when it strikes.

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--	Percy
	EvC Forum Director

That looks like a bug to me. All dates and times are supposed to be rendered in the format specified on the member's profile page of the member reading the message, not that of the message author. It looks like this isn't happening for edit date/time tags. I no longer recall the issues I faced while implementing this, either I was constained in what I could do or it's a bug, I'll take a look at the code tonight.

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--	Percy
	EvC Forum Director

I'm becoming increasingly concerned about website performance. It seems like it has become increasing slower over the course of this year. I do plan to investigate soon whether the fault lies with the server or the board software, but there's another possibility that I wonder if anyone has some informed ideas about.One measure that some people might have noticed creeping up is the number of visitors at the site at any given time. It's generally in the range of 400 to 600 visitors. I don't think they're all lurkers. We're indexed by all the major search engines and a few minor ones, too, which is good, but it might also be part of the problem. Sites like Google and Yahoo are always among the top consumers of our bandwidth, but worse than that, I think that EvC Forum must frequently pop up in answer to searches, and this is confirmed by site statistics. Many visitors to the site arrive here through what are called "referrals", and Google and Yahoo are very common referral sites. This means that most of the visitors aren't lurkers, but just people seeking information who are passing through.Yesterday I did a couple of rough measures and discovered that on average a page at the site is visited about 120 times per minute. Each page access requires compilation and interpretation of about 36,000 lines of Perl code. Does anyone out there have a gauge on whether this is a significant server load or not? It seems like a lot to me, but I other than what I do to keep the site going I have no background in this area.Thanks for any info!

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--	Percy
	EvC Forum Director

Since Perl is interpreted, I imagine it's doing at least a thousand machine instructions per line just for compilation. And since Perl is a compact language, post-compilation interpretation of a line could take millions of instructions, e.g., this performs a text substitution on all locations of an array that could be of any conceivable size, and the text strings could also be of any conceivable size, such as the contents of an entire message: About six months ago I gave our server name server responsibility. In other words, instead of delegating lookup of the name "" to some anonymous name server, our server now performs this lookup itself. That means our server gets invoked every time anybody anywhere clicks on a link to . But no name server process appears in the list of most active processes, so I don't think this is a contributor unless the overhead expresses itself in some more subtle way. There's the MySQL calls, too. Membership is already in MySQL, and the next version will move the forums, threads and messages to MySQL, too.Another possible contributor to poor performance could be the size of the message database. We never delete anything, so it could be a case of too much time being spent reading and searching long files containing lists of threads and messages.As someone above noted, posting a message takes a long time. Figuring out why could be an important clue, but this problem only manifests itself on the server, not on my development machine, and so investigating this while the site is active has to be done carefully.

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--	Percy
	EvC Forum Director

You are correct about the performance advantages. I investigated a possible conversion to mod-perl a couple years ago and found that initialization was a significant problem. When you run a Perl program from scratch, it's compiled, initialized and then interpreted. When you run in mod-perl, the Perl program is compiled once, initialized once, then repeatedly interpreted. The variable values at the next invocation are whatever they were at the end of the previous invocation. So everywhere in the program where something like this takes place that depends upon a variable beginning in the undefined state has to be modified, like this example which has to be modified from this: To this: Not much of a change, but the places where you're doing something like this are not usually so obvious. And, if I didn't make this clear enough before, THERE ARE 36,000 LINES OF CODE TO BE EXAMINED FOR SUCH CASES. Sorry for shouting.That's not the only issue raised by mod-perl, but I should have kept a list because I find I don't recall details at this point.So, can I put you in charge of the EvC Forum Mod-Perl Conversion Project?

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--	Percy
	EvC Forum Director