> > Indeed. But whatever "new" we design for the scan will users complain "last week it was enough to restart the logger, now what do I have to do". So nothing 
> > is perfect. But having a button in the ODB editor like "Rebuild history database" might look more elegant. One issue is that it needs special treatment, since 
> > the logger (in the Mu3e experiment) needs >10s for the scan, so a simple rpc call will timeout.
> > 
> 
> I like the elegance of "just restart the logger".
> 
> Having a web page button to tell logger to rescan the history is cumbersome technically,
> (web page calls mjsonrpc to mhttpd, mhttpd calls a midas rpc to mlogger "please set a flag to rescan the history",
> then web page polls mhttpd to poll mlogger for "are you done yet?". or instead of polling,
> deal with double timeouts, in midas rpc to mlogger and mjsronrpc timeout in javascript).
> 
> And to avoid violating (2) above, we must tell user "you cannot push this button during a run!".
> 
> I say, let's take the low road for now and see if it's good enough:
> 
> a) have the history system report any changes in midas.log - "history event added", "new history variable added" (or "renamed"),
>    this will let user see that their changes to the equipment frontend "took" and flag any accidental/unwanted changes.
> 
> b) have mlogger periodically scan ODB and set a "please restart me" flag. observe this flag in the history editor
>    and tell the user "please restart the logger to see latest changes in the history".

This seems like a reasonable plan to me (combined with clear documentation).

Thomas