Hi!
On Mar 17, Ingo Strüwing wrote:
> Sergei Golubchik, 17.03.2008 16:12:
> ...
> > On Mar 12, Ingo Strüwing wrote:
> ...
> > How would you, without a global variable, synchronize with threads
> > that are not connection threads ?
>
> I didn't have it in mind when designing the feature. The use cases I
> had in mind included connection threads only.
>
> Do you want to have it in the initial implementation? Or can we take
> it as a potential extension for later?
As you don't need it now apparently and Backup guys don't need it
either, let us keep this idea as a potential extension for later.
Could you add it as a @todo comment to sys_var_debug_sync::check, where you
prevent updates to a global variable ?
> Possible problems with GLOBAL synchronization could be:
>
> - Every thread is affected, even the requesting one. Precautions must be
> taken that only the right thread executes the action.
Yes. But a special action IGNORE could help (works like ignore in gdb
breakpoints).
> - Mikael told me that DBAs use to experiment with everything, even on a
> production system. Blocking the own thread forever is bad enough, but
> allowing for blocking everything sounds even worse.
Remember that an action is removed when executed.
To really block everything one needs to use EXECUTE N, with N > number
of running threads.
Regards / Mit vielen Grüssen,
Sergei
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