Get Sessions from Application
Hi all, I've a problem with my last app: We use our app as a WebService that provide license for our products and donwload upgrades, and a Web Site for Support. It has happen (today) that we make some changes, so shutdown the app, while someone was downloading an update. You can easly image that our customer wasn't happy about this I was thinking to prepare a method in Application for searching in active session if someone is logged in, and display it in the admin panel, but I wasn't able to find out how to access to the sessions. Is there a way to do this, or not? I will thank you for every advices -- Daniele Corti AIM: S0CR4TE5 Messenger: [EMAIL PROTECTED] -- Computers are like air conditioners -- they stop working properly if you open WINDOWS -- What about the four lusers of the apocalypse? I nominate: advertising, can't log in, power switch and what backup? --Alistair Young ___ Do not post admin requests to the list. They will be ignored. Webobjects-dev mailing list (Webobjects-dev@lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/webobjects-dev/archive%40mail-archive.com This email sent to [EMAIL PROTECTED]
Re: In WOComponent constructor and need to go to another WOComponent and not come back
Hi! The constructor is an odd place for this. The constructor is called from pageWithName(). That is in the request- response loop preceding the one that would actually use the component. If you already know at that point in time where you want to go and where not, you should modify the caller so that pageWithName() is called with the correct arguments. There might nonetheless be situations where you may want to forbid viewing a certain page. E.g. it is a private page and you want a safety net just in case some day someone writes code that doesn't check access right before going to the page. For that I would code a check in the awake() method. If the check fails throw an exception. Optionally that exception could carry information on where to take the user. The exception handler in your Application class should take care of routing the user to the appropriate page. Pierre On Sep 5, 2007, at 2:41 AM, Baiss Eric Magnusson wrote: I'm in the Constructor of a WOComponent sub-class and I realize I have to be in another page. I invoke a new pageWithName, but then what? Baiss Eric Magnusson http://www.Track-Your-Finances.com http://www.CascadeWebDesign.com ___ Do not post admin requests to the list. They will be ignored. Webobjects-dev mailing list (Webobjects-dev@lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/webobjects-dev/webobjects-lists%40houdah.com This email sent to [EMAIL PROTECTED] ___ Do not post admin requests to the list. They will be ignored. Webobjects-dev mailing list (Webobjects-dev@lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/webobjects-dev/archive%40mail-archive.com This email sent to [EMAIL PROTECTED]
Re: Get Sessions from Application
Assuming you're not using a servlet deployment: WOServerSessionStore sessionStore = (WOServerSessionStore) WOApplication.application().sessionStore(); NSArray sessions = sessionStore._sessions().allValues(); Note that this will only return the sessions that exist within a single instance. If you are running multiple instances, you would need to check each instance. Also, SessionStore does not expose the last access time as public -- we add that to our base session subclass and touch the value in session.awake() so you can tell if the sessions are recently used. I don't recall if Session has a method that tells you if its currently checked out or not, either, but you can also add a boolean check to at least see if the session is currently awake or not. ms On Sep 5, 2007, at 4:10 AM, Daniele Corti wrote: Hi all, I've a problem with my last app: We use our app as a WebService that provide license for our products and donwload upgrades, and a Web Site for Support. It has happen (today) that we make some changes, so shutdown the app, while someone was downloading an update. You can easly image that our customer wasn't happy about this I was thinking to prepare a method in Application for searching in active session if someone is logged in, and display it in the admin panel, but I wasn't able to find out how to access to the sessions. Is there a way to do this, or not? I will thank you for every advices -- Daniele Corti AIM: S0CR4TE5 Messenger: [EMAIL PROTECTED] -- Computers are like air conditioners -- they stop working properly if you open WINDOWS -- What about the four lusers of the apocalypse? I nominate: advertising, can't log in, power switch and what backup? --Alistair Young ___ Do not post admin requests to the list. They will be ignored. Webobjects-dev mailing list (Webobjects-dev@lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/webobjects-dev/mschrag% 40mdimension.com This email sent to [EMAIL PROTECTED] ___ Do not post admin requests to the list. They will be ignored. Webobjects-dev mailing list (Webobjects-dev@lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/webobjects-dev/archive%40mail-archive.com This email sent to [EMAIL PROTECTED]
Re: Get Sessions from Application
2007/9/5, Mike Schrag [EMAIL PROTECTED]: Assuming you're not using a servlet deployment: WOServerSessionStore sessionStore = (WOServerSessionStore) WOApplication.application().sessionStore(); NSArray sessions = sessionStore._sessions().allValues(); Thanks that's what I need! Note that this will only return the sessions that exist within a single instance. If you are running multiple instances, you would need to check each instance. Also, SessionStore does not expose the last access time as public -- we add that to our base session subclass and touch the value in session.awake() so you can tell if the sessions are recently used. I don't think I will need a too accurated value, I only need to know if a variable in the Session is setted: I mean, I use an Enterprise Object GWSUser to memorize witch user is logged in in each session, so I only need to know if it there are users logged in and how many they are I don't recall if Session has a method that tells you if its currently checked out or not, either, but you can also add a boolean check to at least see if the session is currently awake or not. ms On Sep 5, 2007, at 4:10 AM, Daniele Corti wrote: Hi all, I've a problem with my last app: We use our app as a WebService that provide license for our products and donwload upgrades, and a Web Site for Support. It has happen (today) that we make some changes, so shutdown the app, while someone was downloading an update. You can easly image that our customer wasn't happy about this I was thinking to prepare a method in Application for searching in active session if someone is logged in, and display it in the admin panel, but I wasn't able to find out how to access to the sessions. Is there a way to do this, or not? I will thank you for every advices -- Daniele Corti AIM: S0CR4TE5 Messenger: [EMAIL PROTECTED] -- Computers are like air conditioners -- they stop working properly if you open WINDOWS -- What about the four lusers of the apocalypse? I nominate: advertising, can't log in, power switch and what backup? --Alistair Young ___ Do not post admin requests to the list. They will be ignored. Webobjects-dev mailing list (Webobjects-dev@lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/webobjects-dev/mschrag%40mdimension.com This email sent to [EMAIL PROTECTED] ___ Do not post admin requests to the list. They will be ignored. Webobjects-dev mailing list (Webobjects-dev@lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/webobjects-dev/ildenae%40gmail.com This email sent to [EMAIL PROTECTED] -- Daniele Corti AIM: S0CR4TE5 Messenger: [EMAIL PROTECTED] -- Computers are like air conditioners -- they stop working properly if you open WINDOWS -- What about the four lusers of the apocalypse? I nominate: advertising, can't log in, power switch and what backup? --Alistair Young ___ Do not post admin requests to the list. They will be ignored. Webobjects-dev mailing list (Webobjects-dev@lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/webobjects-dev/archive%40mail-archive.com This email sent to [EMAIL PROTECTED]
Re: Get Sessions from Application
Be very careful accessing values of a session ... Make sure you lock properly. On Sep 5, 2007, at 9:05 AM, Daniele Corti wrote: 2007/9/5, Mike Schrag [EMAIL PROTECTED]: Assuming you're not using a servlet deployment: WOServerSessionStore sessionStore = (WOServerSessionStore) WOApplication.application().sessionStore(); NSArray sessions = sessionStore._sessions().allValues(); Thanks that's what I need! Note that this will only return the sessions that exist within a single instance. If you are running multiple instances, you would need to check each instance. Also, SessionStore does not expose the last access time as public -- we add that to our base session subclass and touch the value in session.awake() so you can tell if the sessions are recently used. I don't think I will need a too accurated value, I only need to know if a variable in the Session is setted: I mean, I use an Enterprise Object GWSUser to memorize witch user is logged in in each session, so I only need to know if it there are users logged in and how many they are I don't recall if Session has a method that tells you if its currently checked out or not, either, but you can also add a boolean check to at least see if the session is currently awake or not. ms On Sep 5, 2007, at 4:10 AM, Daniele Corti wrote: Hi all, I've a problem with my last app: We use our app as a WebService that provide license for our products and donwload upgrades, and a Web Site for Support. It has happen (today) that we make some changes, so shutdown the app, while someone was downloading an update. You can easly image that our customer wasn't happy about this I was thinking to prepare a method in Application for searching in active session if someone is logged in, and display it in the admin panel, but I wasn't able to find out how to access to the sessions. Is there a way to do this, or not? I will thank you for every advices -- Daniele Corti AIM: S0CR4TE5 Messenger: [EMAIL PROTECTED] -- Computers are like air conditioners -- they stop working properly if you open WINDOWS -- What about the four lusers of the apocalypse? I nominate: advertising, can't log in, power switch and what backup? --Alistair Young ___ Do not post admin requests to the list. They will be ignored. Webobjects-dev mailing list (Webobjects-dev@lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/webobjects-dev/mschrag% 40mdimension.com This email sent to [EMAIL PROTECTED] ___ Do not post admin requests to the list. They will be ignored. Webobjects-dev mailing list ( Webobjects-dev@lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/webobjects-dev/ildenae% 40gmail.com This email sent to [EMAIL PROTECTED] -- Daniele Corti AIM: S0CR4TE5 Messenger: [EMAIL PROTECTED] -- Computers are like air conditioners -- they stop working properly if you open WINDOWS -- What about the four lusers of the apocalypse? I nominate: advertising, can't log in, power switch and what backup? --Alistair Young ___ Do not post admin requests to the list. They will be ignored. Webobjects-dev mailing list (Webobjects-dev@lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/webobjects-dev/archive%40mail-archive.com This email sent to [EMAIL PROTECTED]
Re: Get Sessions from Application
2007/9/5, Mike Schrag [EMAIL PROTECTED]: Be very careful accessing values of a session ... Make sure you lock properly. Well, I'm only reading them, not writing On Sep 5, 2007, at 9:05 AM, Daniele Corti wrote: 2007/9/5, Mike Schrag [EMAIL PROTECTED]: Assuming you're not using a servlet deployment: WOServerSessionStore sessionStore = (WOServerSessionStore) WOApplication.application().sessionStore(); NSArray sessions = sessionStore._sessions().allValues(); Thanks that's what I need! Note that this will only return the sessions that exist within a single instance. If you are running multiple instances, you would need to check each instance. Also, SessionStore does not expose the last access time as public -- we add that to our base session subclass and touch the value in session.awake() so you can tell if the sessions are recently used. I don't think I will need a too accurated value, I only need to know if a variable in the Session is setted: I mean, I use an Enterprise Object GWSUser to memorize witch user is logged in in each session, so I only need to know if it there are users logged in and how many they are I don't recall if Session has a method that tells you if its currently checked out or not, either, but you can also add a boolean check to at least see if the session is currently awake or not. ms On Sep 5, 2007, at 4:10 AM, Daniele Corti wrote: Hi all, I've a problem with my last app: We use our app as a WebService that provide license for our products and donwload upgrades, and a Web Site for Support. It has happen (today) that we make some changes, so shutdown the app, while someone was downloading an update. You can easly image that our customer wasn't happy about this I was thinking to prepare a method in Application for searching in active session if someone is logged in, and display it in the admin panel, but I wasn't able to find out how to access to the sessions. Is there a way to do this, or not? I will thank you for every advices -- Daniele Corti AIM: S0CR4TE5 Messenger: [EMAIL PROTECTED] -- Computers are like air conditioners -- they stop working properly if you open WINDOWS -- What about the four lusers of the apocalypse? I nominate: advertising, can't log in, power switch and what backup? --Alistair Young ___ Do not post admin requests to the list. They will be ignored. Webobjects-dev mailing list (Webobjects-dev@lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/webobjects-dev/mschrag%40mdimension.com This email sent to [EMAIL PROTECTED] ___ Do not post admin requests to the list. They will be ignored. Webobjects-dev mailing list ( Webobjects-dev@lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/webobjects-dev/ildenae%40gmail.com This email sent to [EMAIL PROTECTED] -- Daniele Corti AIM: S0CR4TE5 Messenger: [EMAIL PROTECTED] -- Computers are like air conditioners -- they stop working properly if you open WINDOWS -- What about the four lusers of the apocalypse? I nominate: advertising, can't log in, power switch and what backup? --Alistair Young ___ Do not post admin requests to the list. They will be ignored. Webobjects-dev mailing list (Webobjects-dev@lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/webobjects-dev/ildenae%40gmail.com This email sent to [EMAIL PROTECTED] -- Daniele Corti AIM: S0CR4TE5 Messenger: [EMAIL PROTECTED] -- Computers are like air conditioners -- they stop working properly if you open WINDOWS -- What about the four lusers of the apocalypse? I nominate: advertising, can't log in, power switch and what backup? --Alistair Young ___ Do not post admin requests to the list. They will be ignored. Webobjects-dev mailing list (Webobjects-dev@lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/webobjects-dev/archive%40mail-archive.com This email sent to [EMAIL PROTECTED]
Re: Get Sessions from Application
On 05.09.2007, at 07:05, Daniele Corti wrote: I don't think I will need a too accurated value, I only need to know if a variable in the Session is setted: I mean, I use an Enterprise Object GWSUser to memorize witch user is logged in in each session, so I only need to know if it there are users logged in and how many they are I do this with a database table that tracks the current users. It's a matter of a couple of minutes to implement this: - create a table in the database, log the session id, a time stamp, the instance, and the current user in Session.awake() (I only update a record for the session id, so I don't have many rows in that table), - delete this row in Session.terminate(), - call Session.terminate() when the user logs out, - write a cleanup method that removes all entries for this instance from the db. This works well and does not have to do dirty things in the sessionStore. Maybe I forgot something here, but that's the basic principle. And in the admin part of the application I have a page showing all entries from that table that updates automatically with an AjaxUpdateContainer - so you can set the instance to refuse new sessions, users get a message (through the PageWrapper) and you can see when they log out. You can even log there current page or whatever they are doing at the moment if you want (I only log the navigation status from ERXNavigation). cug ___ Do not post admin requests to the list. They will be ignored. Webobjects-dev mailing list (Webobjects-dev@lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/webobjects-dev/archive%40mail-archive.com This email sent to [EMAIL PROTECTED]
Re: Get Sessions from Application
On Sep 5, 2007, at 1:10 AM, Daniele Corti wrote: Hi all, I've a problem with my last app: We use our app as a WebService that provide license for our products and donwload upgrades, and a Web Site for Support. It has happen (today) that we make some changes, so shutdown the app, while someone was downloading an update. You can easly image that our customer wasn't happy about this I am wondering if this is really a code problem or just a deployment administration problem. You need to make some app changes so you: 1. Install the new version 2. Create, configure, schedule and start X new instances of the application 3. Unschedule the instances of the previous version and set to Refuse New Sessions Now the logged in users on the old version can finish what they were doing. When their sessions time out, the apps will terminate. Users arriving at your site after this get sent to the new instances. No need for code changes. Chuck I was thinking to prepare a method in Application for searching in active session if someone is logged in, and display it in the admin panel, but I wasn't able to find out how to access to the sessions. Is there a way to do this, or not? I will thank you for every advices -- Daniele Corti AIM: S0CR4TE5 Messenger: [EMAIL PROTECTED] -- Practical WebObjects - for developers who want to increase their overall knowledge of WebObjects or who are trying to solve specific problems. http://www.global-village.net/products/practical_webobjects ___ Do not post admin requests to the list. They will be ignored. Webobjects-dev mailing list (Webobjects-dev@lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/webobjects-dev/archive%40mail-archive.com This email sent to [EMAIL PROTECTED]
Deadlocks
Hi - We're experiencing some pretty bad deadlock issues at the moment and I'm pretty convinced it's down to EC lock abuse. Can anyone confirm that if we follow these rules: ** If you do want all that Wonder magic and love: 1) extend ERXApplication 2) extend ERXSession 3) use ERXEC.newEditingContext() instead of new EOEditingContext() 4) Add to Properties: er.extensions.ERXApplication.useEditingContextUnlocker=true er.extensions.ERXEC.defaultAutomaticLockUnlock=true er.extensions.ERXEC.useSharedEditingContext=false er.extensions.ERXEC.defaultCoalesceAutoLocks=true ... we should never have to manually lock or unlock an EC ? Or put another way, when using these rules is there any situation that we would have to call ec.lock() or ec.unlock() in our code ? Thanks, Simon ___ Do not post admin requests to the list. They will be ignored. Webobjects-dev mailing list (Webobjects-dev@lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/webobjects-dev/archive%40mail-archive.com This email sent to [EMAIL PROTECTED]
Re: Deadlocks
On 05.09.2007, at 16:01, Simon McLean wrote: We're experiencing some pretty bad deadlock issues at the moment and I'm pretty convinced it's down to EC lock abuse. Get a stacktrace of your running application to verify that: http://tinyurl.com/3bpkkv ... we should never have to manually lock or unlock an EC ? That is true, yes - but you still might run into problems if you do bad things. Or put another way, when using these rules is there any situation that we would have to call ec.lock() or ec.unlock() in our code ? I normally lock and unlock manually on long response pages / tasks, as the unlocking of editing contexts relies on the request response loop. If you see problems in the stacktrace, when the session gets checked out from the session store, make sure you NEVER EVER touch something from the session's default editing context inside your performAction method on a long response page. This will autolock your session's default editing context, it will not get unlocked, because you are outside of the rr loop and the next checkout for that session will fail. The other thing I saw with deadlocks: if you run out of space on your server, log4j might deadlock. cug ___ Do not post admin requests to the list. They will be ignored. Webobjects-dev mailing list (Webobjects-dev@lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/webobjects-dev/archive%40mail-archive.com This email sent to [EMAIL PROTECTED]
Re: Deadlocks
If you see problems in the stacktrace, when the session gets checked out from the session store, make sure you NEVER EVER touch something from the session's default editing context inside your performAction method on a long response page. This will autolock your session's default editing context, it will not get unlocked, because you are outside of the rr loop and the next checkout for that session will fail. This particular deadlock should be fixed as of a couple weeks ago after we talked, btw ... I think I rolled autolocking into long response, also. But generally speaking, if you're in another thread, I would lock manually to be safe. Also, if you ever access an EODatabaseContext directly, you MUST lock that yourself. It will not autolock, and that will cause terrible problems. ms ___ Do not post admin requests to the list. They will be ignored. Webobjects-dev mailing list (Webobjects-dev@lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/webobjects-dev/archive%40mail-archive.com This email sent to [EMAIL PROTECTED]
Re: Deadlocks
On Sep 5, 2007, at 3:01 PM, Simon McLean wrote: Hi - We're experiencing some pretty bad deadlock issues at the moment and I'm pretty convinced it's down to EC lock abuse. What makes you think that? As Guido indicated, if you don't have stack traces you are just guessing. Guessing is not an effective form of debugging. :-) Can anyone confirm that if we follow these rules: ** If you do want all that Wonder magic and love: 1) extend ERXApplication 2) extend ERXSession 3) use ERXEC.newEditingContext() instead of new EOEditingContext() 4) Add to Properties: er.extensions.ERXApplication.useEditingContextUnlocker=true er.extensions.ERXEC.defaultAutomaticLockUnlock=true er.extensions.ERXEC.useSharedEditingContext=false er.extensions.ERXEC.defaultCoalesceAutoLocks=true ... we should never have to manually lock or unlock an EC ? Or put another way, when using these rules is there any situation that we would have to call ec.lock() or ec.unlock() in our code ? You are probably safe for general EC usage there, but you can still do other bad things and end up deadlocked. Chuck -- Practical WebObjects - for developers who want to increase their overall knowledge of WebObjects or who are trying to solve specific problems. http://www.global-village.net/products/practical_webobjects ___ Do not post admin requests to the list. They will be ignored. Webobjects-dev mailing list (Webobjects-dev@lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/webobjects-dev/archive%40mail-archive.com This email sent to [EMAIL PROTECTED]
Re: Deadlocks
You are probably safe for general EC usage there, but you can still do other bad things and end up deadlocked. There are many great things in the win column for WebObjects, but I believe one of the definite negatives of the technology is how ridiculously easy it is to deadlock a webobjects application. You have to take the bad with the good. This is miserably scary and nasty until you learn to dump the thread stack traces (see the URL Guido posted earlier: http://tinyurl.com/3bpkkv. Learning the tricks shown here cost me a week of sleep once, but now it's beautifully documented, so profit from the work people have done to write up these instructions). Once you have the stack traces in hand, it becomes pretty obvious where the problem is and you can fix it. Look for the thread which isn't stuck in a wait queue or sleeping while waiting for requests. Mark ___ Do not post admin requests to the list. They will be ignored. Webobjects-dev mailing list (Webobjects-dev@lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/webobjects-dev/archive%40mail-archive.com This email sent to [EMAIL PROTECTED]
Re: Deadlocks
On Sep 5, 2007, at 4:12 PM, Steven Mark McCraw wrote: You are probably safe for general EC usage there, but you can still do other bad things and end up deadlocked. There are many great things in the win column for WebObjects, but I believe one of the definite negatives of the technology is how ridiculously easy it is to deadlock a webobjects application. Is it easy? Or is that just the nature of the concurrency beast? The only ways to cause deadlock that I can think of are (a) improper exception handling related to releasing locks and (b) unbalanced lock usage. I'd expect those to cause problems in any multi-threaded, concurrent environment. There _were_ some issues in this area in prior versions. AFAIK, these are fixed. The one thing I can think of that WO could have added is some try...catch or try...finally blocks in WOSession. These could, if present, handle when the developer does not properly handle the exceptions that happen in their code. Can you think of anything else that could be done? Chuck You have to take the bad with the good. This is miserably scary and nasty until you learn to dump the thread stack traces (see the URL Guido posted earlier: http://tinyurl.com/3bpkkv. Learning the tricks shown here cost me a week of sleep once, but now it's beautifully documented, so profit from the work people have done to write up these instructions). Once you have the stack traces in hand, it becomes pretty obvious where the problem is and you can fix it. Look for the thread which isn't stuck in a wait queue or sleeping while waiting for requests. Mark -- Practical WebObjects - for developers who want to increase their overall knowledge of WebObjects or who are trying to solve specific problems. http://www.global-village.net/products/practical_webobjects ___ Do not post admin requests to the list. They will be ignored. Webobjects-dev mailing list (Webobjects-dev@lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/webobjects-dev/archive%40mail-archive.com This email sent to [EMAIL PROTECTED]
Re: Deadlocks
If virtue can't be mine alone at least my faults can be my own. - Piet Hein Deadlocks in WebObjects have always been my own fault. I'm thankful to Andrew Lindesay's HOWTO. It's a super easy process -- and saves my bacon from my own carelessness. From: Steven Mark McCraw [EMAIL PROTECTED] Date: Wed, 5 Sep 2007 20:22:42 -0400 To: Chuck Hill [EMAIL PROTECTED] Cc: WebObjects (Group) webobjects-dev@lists.apple.com Subject: Re: Deadlocks Is it easy? Or is that just the nature of the concurrency beast? I consider it easy because I've had to deal with it so many times. I think WebObjects seems worse than a normal multithreaded app because things you do that are totally unrelated to concurrency from the programmer's point of view can cause you deadlock. Deadlocks sure are frustrating. In my opinion WO locks are only more noticeable than other web app environments, because, in classical WO programming, you've only got one channel to the DB per application. Lock that up -- and the rest of the app is toast. Other programming environments might suffer less by having more avenues to the data. You might be equally guilty of poor practice in those environments but possibly not even notice it. Instead you reboot your app when it slows to a crawl, or runs out of descriptors, blaming it on Java. It's nice that so much of the concurrency-handling misery you would ordinarily have to think about with multithreaded applications is hidden from you, but when it goes wrong, it is the height of confusion. Well when we see that copy of open-source WO, Real Soon Now (tm). we can all say what confusion? -=- matt Matthew Taylor Northwestern University smime.p7s Description: S/MIME cryptographic signature ___ Do not post admin requests to the list. They will be ignored. Webobjects-dev mailing list (Webobjects-dev@lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/webobjects-dev/archive%40mail-archive.com This email sent to [EMAIL PROTECTED]
