Re: [WebDNA] Re: exclusivelock

This WebDNA talk-list message is from

2011

It keeps the original formatting. numero = 107018
interpreted = N
texte = I'm saying I don't know how exclusivelock actually works, and I don't know what issues we should (or must) keep in mind when using it.Sincerely,Kenneth Grome> I went back to re-read Grant's comment.> > Is he or are you saying that webdna does not handle its> own threads in a coherent way or that webdna versus> other programs presents a problem or both? I thought> webdna would handle multiple accesses of a db no> problem. I had thought exclusivelock was more for> transaction-like database access to ensure inconsistent> changes were not made (which I do not need yet).> > How would you test this exclusive lock scenario? Perhaps> a lock via a 10-20 second loop and then hit the db via> another script?> > Bill> > On Thu, Jul 21, 2011 at 10:33 AM, Aaron Michael Kaczmarek> > wrote:> > You got me on the hook!> > > > On 7/21/11 10:16 AM, Govinda wrote:> >> Great questions Ken!> >> I would also really like to read a definitive (more> >> comprehensive) article on that context.> >> > >> -Govinda> >> > >> On 2011-07-21, at 7:24 AM, Kenneth Grome wrote:> >>>> Should I use exclusivelock on a db I want to> >>>> replace?> >>> > >>> Are there other reasons why I should not use> >>> exclusivelock as shown in the example below?> >>> > >>> Are there better ways to insure that this.db gets> >>> replaced completely in RAM and on disk before the> >>> next visitor requests a page that opens this.db> >>> again?> >>> > >>> Does anyone have a clue about how exclusivelock> >>> actually works? For example, can WebDNA acquire an> >>> exclusivelock on a database that is closed? Or does> >>> it have to open the db in order to acquire the lock?> >>> > >>> What happens when a db is open when the exclusivelock> >>> is acquired? Can the db be closed and the file> >>> deleted inside the exclusivelock context?> >>> > >>> Sorry if these questions seem anal, but using> >>> exclusivelock at all suggests that we need to do> >>> something critically important to the db, and if it> >>> doesn't work the way we think it does, we could be> >>> making really bad assumptions and possibly putting> >>> our data at risk.> >>> > >>> I never used exclusivelock before, and it seems that> >>> not many other people have either. But after> >>> Grant's post last week I get the feeling that we> >>> should be using it in a lot of situations where we> >>> are not. So I'm just trying to get a clearl> >>> understanding of its limitations, and how it> >>> actually works.> >>> > >>> Sincerely,> >>> Kenneth Grome> >>> > >>>> Should I use exclusivelock on a db I want to> >>>> replace? Is this the proper way to use> >>>> exclusivelock?> >>>> > >>>> [exclusivelock db=this.db]> >>>> [closedatabase this.db]> >>>> [deletefile this.db]> >>>> [copyfile from=new.db&to=this.db]> >>>> [/exclusivelock]> >>>> > >>>> ... or does exclusivelock hold this.db OPEN thus> >>>> preventing it from closing and therefore preventing> >>>> it from being replaced by the new.db?> >>>> > >>>> Sincerely,> >>>> Kenneth Grome> >> > >> ------------------------------------------------------> >> --- This message is sent to you because you are> >> subscribed to the mailing list.> >> To unsubscribe, E-mail to:> >> archives: http://mail.webdna.us/list/talk@webdna.us> >> Bug Reporting: support@webdna.us> > > > -------------------------------------------------------> > -- This message is sent to you because you are> > subscribed to the mailing list .> > To unsubscribe, E-mail to: > > archives: http://mail.webdna.us/list/talk@webdna.us> > Bug Reporting: support@webdna.us> > ---------------------------------------------------------> This message is sent to you because you are subscribed to> the mailing list .> To unsubscribe, E-mail to: > archives: http://mail.webdna.us/list/talk@webdna.us> Bug Reporting: support@webdna.us Associated Messages, from the most recent to the oldest:

[WebDNA] exclusivelock (Kenneth Grome 2011)

I'm saying I don't know how exclusivelock actually works, and I don't know what issues we should (or must) keep in mind when using it.Sincerely,Kenneth Grome> I went back to re-read Grant's comment.> > Is he or are you saying that webdna does not handle its> own threads in a coherent way or that webdna versus> other programs presents a problem or both? I thought> webdna would handle multiple accesses of a db no> problem. I had thought exclusivelock was more for> transaction-like database access to ensure inconsistent> changes were not made (which I do not need yet).> > How would you test this exclusive lock scenario? Perhaps> a lock via a 10-20 second loop and then hit the db via> another script?> > Bill> > On Thu, Jul 21, 2011 at 10:33 AM, Aaron Michael Kaczmarek> > wrote:> > You got me on the hook!> > > > On 7/21/11 10:16 AM, Govinda wrote:> >> Great questions Ken!> >> I would also really like to read a definitive (more> >> comprehensive) article on that context.> >> > >> -Govinda> >> > >> On 2011-07-21, at 7:24 AM, Kenneth Grome wrote:> >>>> Should I use exclusivelock on a db I want to> >>>> replace?> >>> > >>> Are there other reasons why I should not use> >>> exclusivelock as shown in the example below?> >>> > >>> Are there better ways to insure that this.db gets> >>> replaced completely in RAM and on disk before the> >>> next visitor requests a page that opens this.db> >>> again?> >>> > >>> Does anyone have a clue about how exclusivelock> >>> actually works? For example, can WebDNA acquire an> >>> exclusivelock on a database that is closed? Or does> >>> it have to open the db in order to acquire the lock?> >>> > >>> What happens when a db is open when the exclusivelock> >>> is acquired? Can the db be closed and the file> >>> deleted inside the exclusivelock context?> >>> > >>> Sorry if these questions seem anal, but using> >>> exclusivelock at all suggests that we need to do> >>> something critically important to the db, and if it> >>> doesn't work the way we think it does, we could be> >>> making really bad assumptions and possibly putting> >>> our data at risk.> >>> > >>> I never used exclusivelock before, and it seems that> >>> not many other people have either. But after> >>> Grant's post last week I get the feeling that we> >>> should be using it in a lot of situations where we> >>> are not. So I'm just trying to get a clearl> >>> understanding of its limitations, and how it> >>> actually works.> >>> > >>> Sincerely,> >>> Kenneth Grome> >>> > >>>> Should I use exclusivelock on a db I want to> >>>> replace? Is this the proper way to use> >>>> exclusivelock?> >>>> > >>>> [exclusivelock db=this.db]> >>>> [closedatabase this.db]> >>>> [deletefile this.db]> >>>> [copyfile from=new.db&to=this.db]> >>>> [/exclusivelock]> >>>> > >>>> ... or does exclusivelock hold this.db OPEN thus> >>>> preventing it from closing and therefore preventing> >>>> it from being replaced by the new.db?> >>>> > >>>> Sincerely,> >>>> Kenneth Grome> >> > >> ------------------------------------------------------> >> --- This message is sent to you because you are> >> subscribed to the mailing list.> >> To unsubscribe, E-mail to:> >> archives: http://mail.webdna.us/list/talk@webdna.us> >> Bug Reporting: support@webdna.us> > > > -------------------------------------------------------> > -- This message is sent to you because you are> > subscribed to the mailing list .> > To unsubscribe, E-mail to: > > archives: http://mail.webdna.us/list/talk@webdna.us> > Bug Reporting: support@webdna.us> > ---------------------------------------------------------> This message is sent to you because you are subscribed to> the mailing list .> To unsubscribe, E-mail to: > archives: http://mail.webdna.us/list/talk@webdna.us> Bug Reporting: support@webdna.us Kenneth Grome

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Re: [WebDNA] Re: exclusivelock

2011

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