Re: [Nmh-workers] Locking (specifically, sequences)

2013-03-09 Thread Ken Hornstein
>Spitballing for a moment: I wonder if we can detect the case where the >sequence file changes out from under an operation. If so, it might be >possible to save the original data, compute a delta of some sort, and >use that to repair the sequence, or punt to the user? Maybe I didn't explain it th

Re: [Nmh-workers] Locking (specifically, sequences)

2013-03-09 Thread chad
On 09 Mar 2013, at 08:57, Ken Hornstein wrote: >> That sounds like a problem to me. Could an inc have to >> wait a half hour for a refile/folder -pack/or any of a >> large number of other operations to finish? > > That's what I was trying to explain. In the inc case, the actual fiddling > tim

Re: [Nmh-workers] Locking (specifically, sequences)

2013-03-09 Thread Ken Hornstein
>That sounds like a problem to me. Could an inc have to >wait a half hour for a refile/folder -pack/or any of a >large number of other operations to finish? That's what I was trying to explain. In the inc case, the actual fiddling time is small. Re-reading the sequence file after you're done in

Re: [Nmh-workers] Locking (specifically, sequences)

2013-03-09 Thread David Levine
Ken wrote: > Yeah, but until (relatively) recently, that could result > in corrupted sequences. I'm just trying to imagine how > people could be doing that since it can break, today. They live with it, I suppose. I don't rely on sequences for anything important. (And shouldn't that be "now" in

Re: [Nmh-workers] Locking (specifically, sequences)

2013-03-09 Thread Ken Hornstein
>> You're running refile the same time as an "inc" or "pick"? > >It can happen, such as with cron jobs. Yeah, but until (relatively) recently, that could result in corrupted sequences. I'm just trying to imagine how people could be doing that since it can break, today. >> I'm trying to see how t

Re: [Nmh-workers] Locking (specifically, sequences)

2013-03-09 Thread David Levine
Ken wrote: > Make sense? Your small examples do, but there's nothing to stop dangerous concurrent operations, which we're starting to get to: > >* a "refile" that made a heckuva mess > > You're running refile the same time as an "inc" or "pick"? It can happen, such as with cron jobs. > I'm tr

Re: [Nmh-workers] Locking (specifically, sequences)

2013-03-09 Thread Ralph Corderoy
> No, and no (read-only archive media? The 1990s called, they want > their CD-ROMs back :-) ). mount(8) has a `ro' option; it's handy to know old stuff isn't going to be accidentally changed and copies of it become out of step. ;-) Cheers, Ralph. __

Re: [Nmh-workers] Locking (specifically, sequences)

2013-03-09 Thread Ken Hornstein
>> Hm. You know ... I never really understood the point of private >> sequences. > >Do you have any folders shared with other users? Or any that are on >read-only archive media? No, and no (read-only archive media? The 1990s called, they want their CD-ROMs back :-) ). I see Norm's use of priva

Re: [Nmh-workers] Locking (specifically, sequences)

2013-03-09 Thread Ken Hornstein
>* a "show" that removed a message from the unseen sequence >* a "mark" that removed anything from any sequence that they use Okay, I think these will be fine. If we have one window running "inc" and another window running "show", let's say at the start of inc we have: unseen: 2-5 inc starts ru

Re: [Nmh-workers] Locking (specifically, sequences)

2013-03-09 Thread David Levine
Ken wrote: > >> So it probably makes sense to there to call seq_read() to read/lock > >> the sequence file after all the messages are searched; that will > >> reload any changes to the sequence file & write-lock it. > > > >What happens if there were changes to the sequence file, > >esp. some

Re: [Nmh-workers] Locking (specifically, sequences)

2013-03-09 Thread Ken Hornstein
>> So it probably makes sense to there to call seq_read() to read/lock >> the sequence file after all the messages are searched; that will >> reload any changes to the sequence file & write-lock it. > >What happens if there were changes to the sequence file, >esp. some that invalidate the (po

Re: [Nmh-workers] Locking (specifically, sequences)

2013-03-09 Thread David Levine
Ken wrote: > So it probably makes sense to there to call seq_read() to read/lock > the sequence file after all the messages are searched; that will > reload any changes to the sequence file & write-lock it. What happens if there were changes to the sequence file, esp. some that invalidate t

Re: [Nmh-workers] Locking (specifically, sequences)

2013-03-09 Thread norm
Ken Hornstein writes: >>That's what I tried to address with a lock-and-read-again (below) >Hm. You know ... I never really understood the point of private sequences. >Why are they used? _Do_ people use them? I do. I like having everything in a single file, where I can see and grok it all and s

Re: [Nmh-workers] Locking (specifically, sequences)

2013-03-09 Thread Ralph Corderoy
Hi Ken, > Hm. You know ... I never really understood the point of private > sequences. Do you have any folders shared with other users? Or any that are on read-only archive media? Cheers, Ralph. ___ Nmh-workers mailing list Nmh-workers@nongnu.org ht