Re: [whatwg] Active workers when user leaves the page
Hi, Could it not be set that a there is a maximum execution time for any workers that are still active, definable by the browser but with a suggested value of say 1000milliseconds in the spec, any processing that takes longer than this is killed, but gives the option for well built scripts and cleanup processes to run gracefully. Martin From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Robert O'Callahan Sent: 08 August 2008 23:30 To: Jonas Sicking Cc: whatwg Subject: Re: [whatwg] Active workers when user leaves the page On Sat, Aug 9, 2008 at 7:01 AM, Jonas Sicking <[EMAIL PROTECTED]> wrote: I do want to be agressive with killing workers when the user leaves a page since that makes for better user experience. However I'm also worried about stopping scripts halfway through breaking things and leaving the site with half-finished operations that are stored in databases or localStorage. Aggressive killing of workers without warning when the user navigates away would actually be a good feature. There are various reasons outside anyone's control that a worker might die abruptly. For example, power failure, browser crash, or "slow-script" style timeout. Applications need to be able to handle those cases, for example by using database transactions or careful use of atomic operations. But that's hard to test and authors probably won't design or test well for those cases since they're relatively uncommon. Expanding abrupt termination scenarios to include navigate-away makes abrupt termination much easier to test, forces authors to design for it early, and will ultimately simplify the application design by reducing the different ways a worker can terminate. This may sound a bit radical, but it's not a new idea. It's a principle sometimes called "crash-only software". See e.g. http://www.usenix.org/events/hotos03/tech/full_papers/candea/candea_html/ Rob -- "He was pierced for our transgressions, he was crushed for our iniquities; the punishment that brought us peace was upon him, and by his wounds we are healed. We all, like sheep, have gone astray, each of us has turned to his own way; and the LORD has laid on him the iniquity of us all." [Isaiah 53:5-6] -- This message has been scanned for viruses and dangerous content by MailScanner <http://www.mailscanner.info/> , and is believed to be clean.
Re: [whatwg] Active workers when user leaves the page
On Sat, Aug 9, 2008 at 7:01 AM, Jonas Sicking <[EMAIL PROTECTED]> wrote: > I do want to be agressive with killing workers when the user leaves a page > since that makes for better user experience. However I'm also worried about > stopping scripts halfway through breaking things and leaving the site with > half-finished operations that are stored in databases or localStorage. > Aggressive killing of workers without warning when the user navigates away would actually be a good feature. There are various reasons outside anyone's control that a worker might die abruptly. For example, power failure, browser crash, or "slow-script" style timeout. Applications need to be able to handle those cases, for example by using database transactions or careful use of atomic operations. But that's hard to test and authors probably won't design or test well for those cases since they're relatively uncommon. Expanding abrupt termination scenarios to include navigate-away makes abrupt termination much easier to test, forces authors to design for it early, and will ultimately simplify the application design by reducing the different ways a worker can terminate. This may sound a bit radical, but it's not a new idea. It's a principle sometimes called "crash-only software". See e.g. http://www.usenix.org/events/hotos03/tech/full_papers/candea/candea_html/ Rob -- "He was pierced for our transgressions, he was crushed for our iniquities; the punishment that brought us peace was upon him, and by his wounds we are healed. We all, like sheep, have gone astray, each of us has turned to his own way; and the LORD has laid on him the iniquity of us all." [Isaiah 53:5-6]
Re: [whatwg] Active workers when user leaves the page
On Fri, 8 Aug 2008, Jonas Sicking wrote: > > This is something that have been in the back of my brain for a few days: > How do we deal with the user navigating a way from a page if there's a > Worker in the middle of some very long running script? Right now the spec says that closing becomes true, and if the worker doesn't clean up promptly, the "kill a worker" algorithm is invoked and the script is killed, the unload handler is handled, and the script is killed again if that doesn't end prompty either. > Also note that the the presence, or lack of, fastback cache doesn't > really make a difference. Pages are eventually going to get purged from > the fastback cache, so it just pushes the problem to a point a little > later in time. Yup, the spec deals with this already too. -- Ian Hickson U+1047E)\._.,--,'``.fL http://ln.hixie.ch/ U+263A/, _.. \ _\ ;`._ ,. Things that are impossible just take longer. `._.-(,_..'--(,_..'`-.;.'
