Changing databases at runtime

[Simon Matter]

Jonathan Marsden schrieb:
> 
> On 25 Nov 2002, Rob Siemborski writes:
> 
> > On 25 Nov 2002, Erik Enge wrote:
> 
> >> I wouldn't rate it as easy unless it was a config option at
> >> run-time, not an option to configure at compile-time.
> 
> > This wouldn't be tremendously hard to do (probably just a matter of
> > replacing some macros with some code that is a bit more clever), but
> > there'd be a (small) performance penalty and there isn't really any
> > intrest in doing it, since converting databases shouldn't be a
> > common operation anyway.
> 
> This is in part a packaging and upgrading issue, though.  Especially
> when the recomended default choices for what databases within Cyrus
> are in what form seem to change over time, and that this may get
> 'worse' as new backends are implemented, the ability to build a
> compiled version of Cyrus that could find and use whatever database
> format it can see (or failing that, whatever database some separate
> utility can see and then edit into the config files), would probably
> help reduce the "I upgraded Cyrus to the latest package, and
> everything broke" type of posts -- which in some cases have reportedly
> led to users giving up on Cyrus altogether.

At least my RPM packages do exactly this. I have put much effort in
creating packages which have build time options for DB backends and DB
conversion is performed automagically on the fly while
installing/upgrading/restarting. I didn't get any feedback until now
about this feature so I expect it works for most people :)
If it doesn't work, let me know.

Simon

> 
> I don't know for sure whether a simple and reliable package upgrade is
> worth "a (small) performance penalty" for the average user of a
> pre-packaged (RPM or .deb) Cyrus, but I suspect it might well be.  And
> over time, such sites may become the majority of Cyrus installations.
> 
> This probably isn't something of great utility to CMU, but for the
> average Linux sysadmin who just wants to grab an RPM or a .deb and
> install it and have Cyrus "just work", upgrading as new RPMs/.debs are
> released, it could be a big deal in the long run.
> 
> Jonathan
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