cookies cookies cookies
How do I reliably remove a cookie from a browser's memory? I've only just begun to experiment but it seems if I set the cookie to "" or undef Apache::ASP doesn't send the right headers to remove the cookie. (Actually undef seems to corrupt the cookie). I could just write a handler to set the header appropriately but I'm not even sure what I should be putting in the header. -- greg
Re: HTTP Mod_Perl mini-server
Perrin Harkins [EMAIL PROTECTED] writes: On Fri, 3 Nov 2000, Vivek Khera wrote: Lately I've been getting very interested in using solid-state disks for high-performance issues. They're expensive, but if you need that much speed, they're worth it. Are they? I tried one once, and it wasn't any faster than my normal disk because I had so much RAM it was all getting buffered already. If you don't have enough RAM, it might help, but I suspect these are more expensive than equivalent amounts of RAM. Solid state disks are very effective for particular applications like mail spools and database logs where the application waits for data to be flushed to disk before continuing. For most normal applications the same effect can be obtained by adding RAM and/or playing with tools like memfs. -- greg - To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
Re: open(FH,'|qmail-inject') fails
Doug MacEachern [EMAIL PROTECTED] writes: On Mon, 25 Sep 2000, Stas Bekman wrote: All you care about is to measure the time between email sending start and end (when the process continues on its execution flow). Why should one care about the details of internal implementation. i only skimmed the first part of this thread, but assumed if you're talking about performance, you'd want to compare the overall impact on your system(s) of Net::SMTP vs. |qmail-inject. you cannot measure the overall impact just using Benchmark.pm is all i'm trying to clarify. A better plan for such systems is to have a queue in your database for parameters for e-mails to send. Insert a record in the database and let your web server continue processing. Have a separate process possibly on a separate machine or possibly on multiple machines do selects from that queue and deliver mail. I think the fastest way is over a single SMTP connection to the mail relay rather than forking a process to inject the mail. This keeps the very variable -- even on your own systems -- mail latency completely out of the critical path for web server requests. Which is really the key measure that dictates the requests/s you can serve. -- greg
Re: multilanguage site
can someone suggest me the best way to build a multilanguage web site (english, french, ..). I'm using Apache + mod_perl + Apache::asp (for applications) I'm really interested in what other people are doing here. We've just released our first cut at i18n and it's going fairly well. But so far we haven't dealt with the big bugaboo, character encoding. One major problem I anticipate is what to do when individual include files are not available in the local language. For iso-8859-1 encoded languages that's not a major hurdle as we can simply use the english text until it's translated. But for other encodings does it make sense to include english text? If we use UTF-8 all the ascii characters would display properly, but do most browsers support UTF-8 now? Or do people still use BIG5, EUS, etc? As far as I can tell there's no way in html to indicate to the browser that a chunk of content is in some other encoding other than what was specified in the headers or meta tag. There's no span charset=... attribute or anything like that. This seems to make truly multilingual pages really awkward. You basically must use an encoding like UTF-8 which can reach the entire unicode character set or else you cannot mix languages. -- greg
problem with mod_proxy/mod_rewrite being used for the front-end proxy
This isn't entirely on-topic but it's a solution often suggested for mod_perl
users so I suspect there are other users here being bitten by the same
problems. In fact the manner in which problems manifest are such that it's
possible that many mod_perl users who are using mod_rewrite/mod_proxy to run
a reverse proxy in front of their heavyweight perl servers have a security
problem and don't even know it.
The problem is that the solution written in the mod_rewrite guide for a
reverse proxy doesn't work as advertised to block incoming proxy requests.
RewriteRule^(http|ftp)://.* - [F]
This is supposed to block incoming proxy requests that aren't specifically
created by the rewrite rules that follow.
The problem is that both mod_rewrite and mod_proxy have changed, and this
seems to no longer catch the incoming proxy requests. Instead mod_rewrite
seems to see just the path part of the URI, ie, /foo/bar/baz.pl without the
http://.../.
I've even tried using ${THE_REQUEST} which actually matches, and says it's
forcing the response to be forbidden, then it happily proxies the request
anyways!
I'm using a
Directory proxy:*
deny from all
/Directory
Directory proxy:http://127.0.0.1/
allow from all
/Directory
section to at least avoid being an open proxy to the outside world, but I
cannot find any way in 1.3.12 to refuse all proxy requests coming from the
outside.
If you're not aware of the problem at all and have merely followed the advice
of the mod_rewrite guide you are probably an open proxy, allowing attackers to
use your web server to attack other sites anonymously.
--
greg
Re: Apache::Perfmon 0.011
Lupe Christoph [EMAIL PROTECTED] writes: Hmm. Apache::Benchmark sounds more like a benchmark driver to me. Apache::Instrumentation or so? Apache::Probe? Profile or even just Prof. I looked at this and really like the idea. Unfortunately I need to recompile my Apache to use it. What I think it needs is, a way to gather the statistics in a hash based on the request. That way I can make a web page that pokes around in the hash table and reports the average and maximum time taken by page. I'm not clear how or if that can be done in a separate module like this that doesn't know how the requests are dispatched. Either a regexp needs to be provided that returns the key to use for the hash, or else something similar needs to be integrated into packages like CGI and Apache::ASP. (Which was the approach I was planning on taking myself.) I like this approach better though, so it would be neat to see it polished. -- greg
Re: speed up/load balancing of session-based sites
Further, what are the standard ways to load balance a session-tracking app across multiple servers when the sessions are stored in memory and a given user has to be consistently sent back to the same machine? Can round-robin DNS be counted on to send people back to the same server over the life of a given session? On my sites I use a central database for storing the session objects, and all of the https servers access this central resource. Obviously if it goes down, everything is toast, but the same can be said of the database that stores all of the customer information, etc. I've written some pretty heavy database driven sites that do some pretty complicated things and I've *never* found it really necessary to have a server side session database. In theory you might find it convenient to cache big complex data structures for the session, but in practice most people use it for storing things like usernames and shopping cart contents. My suggestion is to put the state information in the cookie directly. Include a crypto hash (with a secret) to sign the cookie and be done with it. If the information is sensitive then encrypt the whole thing. Then your sessions are completely stateless, they can migrate between mod_perl processes, even across servers. They can even survive server reboots. And They don't require additional infrastructure to store the database of sessions. I keep meaning to write this up as an Apache:: module, but it's pretty trivial to cons up an application-specific version. The only thing this doesn't provide is a way to deal with large data structures. But generally if the application is big enough to need such data structures you have a real database from which you can reconstruct the data on each request, just store the state information in the cookie. -- greg
Re: modproxy:modperl ratios...
A few lessons on this arena: 1) Move your pictures to another server *even if you're using a proxy* Search back in the archives for my previous post on this topic. 2) If you use mod_proxy you can give it the same web root and have it serve some static objects itself instead of having to cache them. But 1) is even better than doing this. Sometimes you might not have a choice, such as with java applets. 3) mod_proxy is poorly designed and poorly implemented. The main deficiency is that each process is responsible for opening and maintaining its connection to the backend. This defeats keep-alives completely and forces a lot of overhead in the kernel and the servers. There's a much better design that involves creating a fixed number of sockets and treating that as a shared pool. In that design the backend can have a long keep-alive timeout and maintain persistent connections to the front-end. Despite these concerns I've been using mod_proxy myself and it does work. I'm planning to change to mod_backhand though which implements 3) but it's new code. -- greg
Re: Killing off children
What state was the process in? There are only two states that a process can be in that won't respond to -9: Zombie (Z in ps), in which case the process is already dead and Apache didn't wait on it properly. This isn't a problem just ignore it unless you can reproduce it in which case report it as an Apache bug. Disk wait (D in ps), which is actually any uninterruptible sleep, usually disk i/o, indicates either something is broken in your kernel or that you're using NFS. In the case of disk wait you can actually get the wait channel from ps and look it up in your kernel symbol table to find out what resource it was waiting on. What you would do with that information isn't clear though. I suppose it might point the way to what component of the system was misbehaving if the problem occurred frequently. Bill Moseley [EMAIL PROTECTED] writes: Yes, a system problem, I guess, if kill -9 doesn't work I'm not sure what will work. I tried a truss, but it reported "truss: cannot control process 3732" which I assume is because it's parent is root, and my cgi was running as nobody. root should be able to truss any process other than init. I suspect this message meant the process was actually a zombie and not really alive at all. -- greg
Re: Caching DBI handles with IPC?
Saar Picker [EMAIL PROTECTED] writes: Thanks for responding. We currently are cacheing DB connections per-process. However, with 40-50 processes per server, and 4+ machines per DB server, and 3-5 connections per process, you can see how the number of connections per DB server gets rather large. I think the problem lies with the CODE references. I'll check out IPC::Shareable some more. Firstly your numbers sound a little odd, a) why do you have more than one connection per process, I assume you're using connection persistent connections of some sort (look at connect_cached for example) b) Why do you run as many as 50 processes, if you split off all the static data onto a separate server you might find things run as fast or faster with fewer processes. c) 100-200 connections might not be out of line for your database. If you're using Oracle you might check into MTS for example which can handle 1000+ connections as easily as 1 connection if they're not doing any more database work. Your problems sharing connections across sessions has nothing to do with perl. A database connection is more than just perl code, it's usually network socket and it's usually managed by a C library from the database vendor. Worse, most databases if not all databases tie the concept of session to the network connection. If two processes end up writing to the same socket the database will be very confused. In any case you can't store a socket in a shared memory segment, it's not just a piece of data. You would need to arrange to open all your sockets before Apache forked or find some other way to distribute them. Then you would need to deal with the fact that your database library stores some state information that would also need to be shared, either putting all of that in shared memory or some other way. And you don't have access to it in perl, you would need to do this in the DBD driver's C code and either use explicit support from the library or add code to the low level DB library. Then you would need to write the perl layer to handle locking the handles to avoid having two processes trying to use the same handle at the same time. In other words, there's a lot of work to be done to do this using shared memory, and not all the libraries would even support it. I'm not completely sure any of them would. DBI::Proxy works by having a single process do all the database work, everything else talks to the proxy. This adds a layer of latency though. Oracle has a native tool called Connection Manager that does something similar. -- greg
Re: Apache::Session, DBD::Oracle
[EMAIL PROTECTED] (Robert Locke) writes: - store this string into Oracle (type is LONG) You really really don't want to be using LONG btw. How large is the data you're really storing anyways? Oracle can do varchars up to 2k unlike some other pesky databases. LONGs have a number of problems, you can't export/import them, you can't create table as select to copy them to a new table etc. They also allegedly make your tables slow to access, though I don't know the details. I don't know if BLOBs are any different though. I do wonder whether you're making good use of your database to be storing information as frozen perl data structures. It's flexible but it can't be very fast and it doesn't buy you the data mining abilities having a database is good for. -- greg
Re: squid performance
Leslie Mikesell [EMAIL PROTECTED] writes: I agree that it is correct to serve images from a lightweight server but I don't quite understand how these points relate. A proxy should avoid the need to hit the backend server for static content if the cache copy is current unless the user hits the reload button and the browser sends the request with 'pragma: no-cache'. I'll try to expand a bit on the details: 1) Netscape/IE won't intermix slow dynamic requests with fast static requests on the same keep-alive connection I thought they just opened several connections in parallel without regard for the type of content. Right, that's the problem. If the two types of content are coming from the same proxy server (as far as NS/IE is concerned) then they will intermix the requests and the slow page could hold up several images queued behind it. I actually suspect IE5 is cleverer about this, but you still know more than it does. By putting them on different hostnames the browser will open a second set of parallel connections to that server and keep the two types of requests separate. 2) static images won't be delayed when the proxy gets bogged down waiting on the backend dynamic server. Picture the following situation: The dynamic server normally generates pages in about 500ms or about 2/s; the mod_perl server runs 10 processes so it can handle 20 connections per second. The mod_proxy runs 200 processes and it handles static requests very quickly, so it can handle some huge number of static requests, but it can still only handle 20 proxied requests per second. Now something happens to your mod_perl server and it starts taking 2s to generate pages. The proxy server continues to get up to 20 requests per second for proxied pages, for each request it tries to connect to the mod_perl server. The mod_perl server can now only handle 5 requests per second though. So the proxy server processes quickly end up waiting in the backlog queue. Now *all* the mod_proxy processes are in "R" state and handling proxied requests. The result is that the static images -- which under normal conditions are handled quicly -- become delayed until a proxy process is available to handle the request. Eventually the backlog queue will fill up and the proxy server will hand out errors. This is a good idea because it is easy to move to a different machine if the load makes it necessary. However, a simple approach is to use a non-mod_perl apache as a non-caching proxy front end for the dynamic content and let it deliver the static pages directly. A short stack of RewriteRules can arrange this if you use the [L] or [PT] flags on the matches you want the front end to serve and the [P] flag on the matches to proxy. That's what I thought. I'm trying to help others avoid my mistake :) Use a separate hostname for your pictures, it's a pain on the html authors but it's worth it in the long run. -- greg
Re: squid performance
Leslie Mikesell [EMAIL PROTECTED] writes: The 'something happens' is the part I don't understand. On a unix server, nothing one httpd process does should affect another one's ability to serve up a static file quickly, mod_perl or not. (Well, almost anyway). Welcome to the real world however where "something" can and does happen. Developers accidentally put untuned SQL code in a new page that takes too long to run. Database backups slow down normal processing. Disks crash slowing down the RAID array (if you're lucky). Developers include dependencies on services like mail directly in the web server instead of handling mail asynchronously and mail servers slow down for no reason at all. etc. The proxy server continues to get up to 20 requests per second for proxied pages, for each request it tries to connect to the mod_perl server. The mod_perl server can now only handle 5 requests per second though. So the proxy server processes quickly end up waiting in the backlog queue. If you are using squid or a caching proxy, those static requests would not be passed to the backend most of the time anyway. Please reread the analysis more carefully. I explained that. That is precisely the scenario I'm describing faults in. -- greg
Re: squid performance
Vivek Khera [EMAIL PROTECTED] writes: Squid does indeed cache and buffer the output like you describe. I don't know if Apache does so, but in practice, it has not been an issue for my site, which is quite busy (about 700k pages per month). I think if you can avoid hitting a mod_perl server for the images, you've won more than half the battle, especially on a graphically intensive site. I've learned the hard way that a proxy does not completely replace the need to put images and other other static components on a separate server. There are two reasons that you really really want to be serving images from another server (possibly running on the same machine of course). 1) Netscape/IE won't intermix slow dynamic requests with fast static requests on the same keep-alive connection 2) static images won't be delayed when the proxy gets bogged down waiting on the backend dynamic server. Both of these result in a very slow user experience if the dynamic content server gets at all slow -- even out of proportion to the slowdown. Eg, if the dynamic content generation becomes slow enough to cause a 2s backlog of connections for dynamic content, then a proxy will not protect the static images from that delay. Netscape or IE may queue those requests after another dynamic content request, and even if they don't the proxy server will eventually have every slot taken up waiting on the dynamic server. So *every* image on the page will have another 2s latency, instead of just a 2s latency for the entire page. This is worst in Netscape of course course where the page can't draw until all the images sizes are known. This doesn't mean having a proxy is a bad idea. But it doesn't replace putting your images on pics.mydomain.foo even if that resolves to the same address and run a separate apache instance for them. -- greg
Re: squid performance
"G.W. Haywood" [EMAIL PROTECTED] writes: Would it be breaching any confidences to tell us how many kilobyterequests per memorymegabyte or some other equally daft dimensionless numbers? I assume the number you're looking for is an ideal ratio between the proxy and the backend server? No single number exists. You need to monitor your system and tune. In theory you can calculate it by knowing the size of the average request, and the latency to generate an average request in the backend. If your pages take 200ms to generate, and they're 4k on average, then they'll take 1s to spool out to a 56kbs link and you'll need a 5:1 ratio. In practice however that doesn't work out so cleanly because the OS is also doing buffering and because it's really the worst case you're worried about, not the average. If you have the memory you could just shoot for the most processes you can handle, something like 256:32 for example is pretty aggressive. If your backend scripts are written efficiently you'll probably find the backend processes are nearly all idle. I tried to use the minspareservers and maxspareservers and the other similar parameters to let apache tune this automatically and found it didn't work out well with mod_perl. What happened was that starting up perl processes was the single most cpu intensive thing apache could do, so as soon as it decided it needed a new process it slowed down the existing processes and put itself into a feedback loop. I prefer to force apache to start a fixed number of processes and just stick with that number. -- greg
Re: oracle : The lowdown
Matt Sergeant [EMAIL PROTECTED] writes: Depends what the business is. If it is a serious business looking for VC I would actually suspect the inverse is true: MySQL is underkill (I think I just made that word up) due to its lack of transactions and other advanced features (yes, these things do mean something in the real world). Actually for web sites the lack of transactions is more of a boon than a problem. Carefully written web pages rarely need complex multiple query transactions anyways. I'm using Oracle now and the single biggest complaint is the unnecessary overhead transactions put in everything even when they're not needed or wanted. For example, it makes it very hard to mix any kind of long running query with OLTP transactions against the same data, since rollback data accumulates very quickly. I would give some appendage for a while to tell Oracle to just use the most recent data for a long running query without attempting to rollback to a consistent view. That said other Oracle features are absolutely essential to web sites: partitioned tables, warm standby databases, hot backups, etc. -- greg
Re: ASP Cookieless Sessions (WAS Re: Apache::ASP)
Joshua Chamas [EMAIL PROTECTED] writes: It reoccured to me just now (back from a sessions methods discussion a long time ago) that these query string cookies might show up in the referer logs of other sites if you have offsite links on your session id pages. I tried a workaround just now where a redirect program would handle offsite links, but the HTTP_REFERER is sticky to the last page visited, and I see no workaround to this security issue. Instead of redirecting them offsite present a page saying "you're about to go offsite" and use a refresh meta tag to send them on their way. If you set the timeout on the refresh to 0 they won't even see the page and I would expect the referrer to still be set. You might even be able to use a refresh header instead of a meta tag and just use a static html page. -- greg
Re: mod_perl-1.21 and apache-1.3.9
I don't think it was Apache's DSO support that was broken, I had httpd working just fine with dynamic everything except mod_perl. mod_perl worked usually but seg faulted with one obscure xs package. I think other similar problems have been observed too. In this case though I think the problem is that he's using the Red Hat binary perl packages, which are known to be bogus. I'm not sure what Red Hat does to their perl but it doesn't work right. hUnTeR [EMAIL PROTECTED] writes: Rasmus Lerdorf wrote: As of Apache-1.3.9, Apache's DSO support really should be stable. I am running a bunch of servers with the DSO version of the PHP module without any problems. -Rasmus I am as well. I have 5 other redhat 6.1 servers running apache-1.3.9 with mod_ssl, mod_perl, openssl, and php and they all run fantastic. But its just this one redhat 5.2 server thats giving me headaches. -- greg
Re: Problems building
Has nobody seen these problems? It seems strange, I had no trouble building 1.3.4+1.19 on Solaris but this is a fresh build on Linux with 1.3.9+1.21 and these errors don't seem to be configuration dependent, they look like generic problems with the build system. What could be wrong? Greg Stark [EMAIL PROTECTED] writes: I'm trying to update to 1.3.9+1.21 but I'm having various problems: 1) The makefile seems to try to run ../apaci even though perl is two levels deep, so it can't find ../apaci, it would have to be ../../apaci === src/modules/perl gcc -I. -I../../include -I../../include/regex -I../../include/.././os/unix -DLINUX=2 -DUSE_HSREGEX -DUSE_EXPAT -I../lib/expat-lite `../apaci` `/data/app/perl/bin/perl -MExtUtils::Embed -e ccopts` -DNO_PERL_RESTART -DMOD_PERL_VERSION=\"1.21\" -I./os/unix -I../../include -c mod_perl_opmask.c -o mod_perl_opmask.o /bin/sh: ../apaci: No such file or directory 2) when it tries to link it gets pages and pages of these errors: gcc -DLINUX=2 -DUSE_HSREGEX -DUSE_EXPAT -I./lib/expat-lite `./apaci`\ -o httpd buildmark.o modules.o modules/perl/libperl.a modules/standard/libstandard.a main/libmain.a ./os/unix/libos.a ap/libap.a regex/libregex.a lib/expat-lite/libexpat.a -lm -lcrypt modules/perl/libperl.a(mod_perl.o): In function `perl_shutdown': mod_perl.o(.text+0xf8): undefined reference to `PL_perl_destruct_level' mod_perl.o(.text+0x102): undefined reference to `PL_perl_destruct_level' mod_perl.o(.text+0x10c): undefined reference to `PL_perl_destruct_level' mod_perl.o(.text+0x13b): undefined reference to `Perl_av_undef' mod_perl.o(.text+0x149): undefined reference to `Perl_sv_free' mod_perl.o(.text+0x161): undefined reference to `Perl_av_undef' 3) Once I got it to build the httpd segfaulted whenever it got a request. Needless to say I'm a bit frustrated :( -- greg -- greg
Re: Memory problems
[EMAIL PROTECTED] writes: Thanks Greg I strongly suggest you move the images to a separate hostname altogether. The proxy is a good idea but there are other useful effects of having a separate server altogether that I plan to write about in a separate message sometime. This does mean rewriting all your img tags though. Look forward to that with interest Briefly the reason you want a separate server and not just a proxy is because netscape and other browsers can do requests in parallel more efficiently. If they're on the same server the browser might choose to queue up a bunch of image downloads on the same connection using keepalives. If it orders them with the slow script generated page first then they get delayed by the length of time it takes the script engine to run. Also if you end up with a backlog queue of proxy servers waiting for a script engine to service them then all your proxy server processes can get stuck waiting for a script engine process. That's fine if all they do is serve dynamic pages but not if they're also responsible for serving static objects. The proxy server may still be useful but it doesn't replace using a separate server on a different hostname or port for the images and static documents. Besides you may eventually want to do that anyways and it will be easier if you've been doing it all along. I have two PIII 500's, so CPU usage is no problem. Amazingly, it's the 1Gig of memory which expires first. That sounds like you have some high-latency job being handled by your perl server. Are they sending mail? Or doing database accesses into a database that can't keep up? If it's just perl it would only take a handful to use 100% cpu, they must be idle waiting for something. I agree with the [EMAIL PROTECTED], if you have to do anything at all dependent on external i/o like sending mail you want to queue up the events and handle them asynchronously. Anything that can arbitrarily increase the latency off the perl httpds is a disaster waiting to happen. Gee, I think I just summarized the two big lessons I was going to write about in the same vein as jb's "in practice" message. I've learned these lessons the hard way, hopefully we can build enough of a repertoire of such lessons in the FAQ to help other people avoid this :) -- greg
Problems building
I'm trying to update to 1.3.9+1.21 but I'm having various problems: 1) The makefile seems to try to run ../apaci even though perl is two levels deep, so it can't find ../apaci, it would have to be ../../apaci === src/modules/perl gcc -I. -I../../include -I../../include/regex -I../../include/.././os/unix -DLINUX=2 -DUSE_HSREGEX -DUSE_EXPAT -I../lib/expat-lite `../apaci` `/data/app/perl/bin/perl -MExtUtils::Embed -e ccopts` -DNO_PERL_RESTART -DMOD_PERL_VERSION=\"1.21\" -I./os/unix -I../../include -c mod_perl_opmask.c -o mod_perl_opmask.o /bin/sh: ../apaci: No such file or directory 2) when it tries to link it gets pages and pages of these errors: gcc -DLINUX=2 -DUSE_HSREGEX -DUSE_EXPAT -I./lib/expat-lite `./apaci`\ -o httpd buildmark.o modules.o modules/perl/libperl.a modules/standard/libstandard.a main/libmain.a ./os/unix/libos.a ap/libap.a regex/libregex.a lib/expat-lite/libexpat.a -lm -lcrypt modules/perl/libperl.a(mod_perl.o): In function `perl_shutdown': mod_perl.o(.text+0xf8): undefined reference to `PL_perl_destruct_level' mod_perl.o(.text+0x102): undefined reference to `PL_perl_destruct_level' mod_perl.o(.text+0x10c): undefined reference to `PL_perl_destruct_level' mod_perl.o(.text+0x13b): undefined reference to `Perl_av_undef' mod_perl.o(.text+0x149): undefined reference to `Perl_sv_free' mod_perl.o(.text+0x161): undefined reference to `Perl_av_undef' 3) Once I got it to build the httpd segfaulted whenever it got a request. Needless to say I'm a bit frustrated :( -- greg
Re: Failing to reconnect after Oracle shutdown abort (Apache::DBI)
Jeffrey Baker [EMAIL PROTECTED] writes:
That's what the driver handle's ping method is for.
if (!$dbh-ping) { reconnect; }
I suppose I could do a ping before every page, but really that's only a kludgy
work-around. Really I would want to do this before every single query, and the
right way to do that is to check every call for errors and handle
those that indicated connection problems by reconnecting. Introducing extra
traffic to do this is a waste.
Unfortunately Oracle doesn't seem to return any one specific error when
disconnected. I've seen a lot of "TNS can't resolve name" type errors (I
forget the number, sorry) and a lot of "hostdef extension not found" which
oerr says is an internal error and indicates a library bug :)
--
greg
Re: Failing to reconnect after Oracle shutdown abort (Apache::DBI)
Tim Bunce [EMAIL PROTECTED] writes: Has anyone experienced a situation where a process (httpd for example) can't reconnect to Oracle after a "shutdown abort"? Tim. As far as I can tell we never get a clean reconnection after any sort of connection problem. I don't even think it takes a shutdown abort to cause this. -- greg
Re: Memory problems
Stas Bekman [EMAIL PROTECTED] writes: I had huge problems yesterday. Our web site made it in to the Sunday Times and has had to serve 1/2 million request in the last 2 days. Oh, I thought there was a /. effect, now it's a sunday effect :) The original concept should be credited to Larry Niven, he called the effect "Flash crowds" Had I set it up to have proxy servers and a separate mod_perl server? No. DOH! So what happened to my 1Gig baby? It died. A sad and unhappy death. I strongly suggest you move the images to a separate hostname altogether. The proxy is a good idea but there are other useful effects of having a separate server altogether that I plan to write about in a separate message sometime. This does mean rewriting all your img tags though. What happened was this: My memory usage went up and up until I got "Out of memory" messages MySQL bailed out. Memory usage was high, and the server was swapping as well. So I thought - restart MySQL and restart Apache. But I couldn't reclaim memory. It was just unavailable. How do you reclaim memory other than by stopping the processes or powering down? Is this something that might have happened because it went past the Out of Memory stage? Have you rebooted yet? Linux has some problems recovering when you run out of memory really badly. I haven't tried debugging but our mail exchangers have done some extremely wonky things once they ran out of memory even once everything had returned to normal. Once non-root users couldn't fork, they just got "Resource unavailable" but root was fine and memory usage was low. First, what you had to do in first place, is to set MaxClients to such a number, that when you take the worst case of the process growing to X size in memory, your machine wouldn't swap. Which will probably return an Error to some of the users, when processes would be able to queue all the requests, but it would never keep your machine down! I claim MaxClients should only be large enough to force 100% cpu usage whether from your database or the perl script. There's no benefit to having more processes running if they're just context switching and splitting the same resources finer. Better to queue the users in the listen queue. On that note you might want to set the BackLog parameter (I forget the precise name), it depends on whether you want users to wait indefinitely or just get an error. -- greg
Re: setting cookies?
I think if you send a 401 in response to a request that contained auth data the user will typically see a "Authentication failed" box, which may look bad compared to just getting the password dialog. Actually I couldn't get this to work a while back, but I didn't try very hard. "Andrei A. Voropaev" [EMAIL PROTECTED] writes: On Mon, Nov 01, 1999 at 05:03:58PM -0500, Robin Berjon wrote: I've never tried this but doesn't sending two 401s in a row for the same document have the auth popup appear again ? I feel like this topic gets slightly confusing. Browser sends request, gets 401 back, asks user for username and password if it doesn't have one cached already. If it has one cached for this particular realm then it attempts to send the cached values. If in response it gets 401 again then it asks user for new username and password for this realm. As far as I know it always takes 2 requests to get protected document. First one returns with 401 code and realm for authentication, second request is done with appropriate user name and password. So if for some reason you decide that some user name and password is not valid any more then you should make sure that if they are sent any number of times later then your authentication handler says no always. Andrei -- -- greg
Re: Failing to reconnect after Oracle shutdown abort (Apache::D BI)
"Young, Geoffrey S." [EMAIL PROTECTED] writes: Incidentally, I have also noticed that on my Linux installation Oracle will not shutdown (or shutdown abort) while any of the httpd processes have persistent connections. That is, httpd must come down first for Oracle to shutdown cleanly. Just thought I'd mention it... There are different kinds of shutdowns shutdown - waits for every connection to disconnect shutdown immediate - cleans up partially executed transactions shutdown abort - leaves dirty blocks on disk which get cleaned up as needed Shutdown immediate can take a while to execute but shutdown abort should be fast. According to people on comp.databases.oracle.server unless you plan to do a backup you can just use shutdown abort. A plain shutdown is useless for web server databases unless you shut down every client including the web server first, and even then it doesn't always seem to work. In our experience pmon sometimes goes wonky if you shutdown abort and then bring the database up. Tech support told us to shutdown abort, bring up the database, then shutdown immediate and bring it up again. The second shutdown cleans up the dirty blocks. I'm not sure if this is just superstition or actually helps but that's what we do now. -- greg
Re: Problem setting up mod_proxy_add_forward
Where was the proxy_add_forward patch again? -- greg
Re: Problem setting up mod_proxy_add_forward
Vivek Khera [EMAIL PROTECTED] writes: "GS" == Greg Stark [EMAIL PROTECTED] writes: GS Where was the proxy_add_forward patch again? It ain't a patch, its a module. The Apache module registry has a pointer to it. Thanks, so where would I find this Apache module registry? It doesn't seem to be linked to off apache.org anywhere. -- greg
Profiling
Does anyone have any idea how much overhead Apache::DProf or Apache::SmallProf add? Will it be possible to use these on a production system without having a severe impact? And has anyone used DBIx::Profile with mod_perl ? All I keep getting is: Can't locate object method "printProfile" via package "DBI::db" at (eval 35) line 4. I can't figure out if this is due to the way i'm loading modules or calling connect or what. I think I've removed all references to Apache::DBI and even made it avoid doing a "use DBI" in case that interferes, but it still does this. -- greg
Re: How to know PID of DB backend ?
Oleg Bartunov [EMAIL PROTECTED] writes: Using ApacheDBI I keep persistent connections between httpd and db. Now I want to know PIDs of httpd children and database backend. For the httpd it's trivial but I don't know where to get PID of db backend. Regards, Oleg That would be entirely dependent on your database, not all databases even start subprocesses. What database are you using? -- greg
Re: Another IE5 complaint
"Joe Pearson" [EMAIL PROTECTED] writes: Hi all, Maybe everyone already knows this, but I just discovered that whenever a IE5 user visits a page in their "Favorites", IE5 also trys to GET favicon.ico from the same site. Therefor I have hundreds of "File does not exist:" errors in my log file. I noticed this a while ago, but I don't see how this is a problem. It's not like returning 404's is really that big a deal for the server. The privacy issues of broadcasting to the server whenever the user sets a favourite is perhaps a bit worrisome though. Can the gimp save .ico files? How big and what colours etc does IE5 expect these to be anyways? -- greg
Re: XML and Apache
There was a database posted on freshmeat specifically designed for storing XML data. I'm not sure what that would mean but perhaps it would be the solution for your problem? "Anthony Gardner" [EMAIL PROTECTED] writes: All, I have a problem. I want to use data in XML format and store it in memory for obvious reasons of speed and to utilise the capabilities of XML. I also want to load the data at server start up time. The problem arises with the size of the data. I end up with six children each with 150MB of data. Needless to say I've run out of memory and the error_log gives error msgs about not being able to fork. -- greg
