On Tue, 2015-02-10 at 23:38 +0000, Stian Soiland-Reyes wrote:
> Are you using the tdb to swap just for reading, or would you need to
> synchronize transactions?
> 
> Below I'll assume you mean 'reading', and that you want to swap
> because you have a 'newer' tdb store from "somewhere".

Yes, that's the use case exactly.

> 
> 
> With fuseki2 (I have not checked with Fuseki 1 which only has a REST
> interface) you can "hot add" a new tdb store in the web interface. If
> the tdb directory with the given name already exist under
> /etc/fuseki/databases it will be re-used and made live immediately.
> 

I currently use fuseki 1 but was looking to upgrade to fuseki2 anyway,
so this sounds like it will solve my problem.

> In my setup I use this in combination with data loading, so that I can
> load "offline" with tdbloader2 and then immediately make it live in an
> existing running Fuseki 2.

I create the new tdb (using tdbloader) and then update a symlink to
target the new tdb. Currently I restart fuseki and the new tdb is read
from the symlink. I want to eliminate the restart. It sounds like the
fuseki2 web interface will allow this.

> 
> There's unfortunately an open issue in the web interface with removing
> and adding a store with the same name -
> https://issues.apache.org/jira/browse/JENA-869 - so if you try this
> now with the current SNAPSHOT of Fuseki 2 you would have to make a new
> database name for every swap and copy the tdb store into that before
> adding it in the user interface.  You could probably hide/simplify
> that name from the URI with a simple Apache httpd ProxyPass or
> RewriteRule

Thanks for the pointers and warning. I'll see if I can work it out.

Regards,
--Paul

> 
> 
> 
> On 10 February 2015 at 19:19, Paul Tyson <[email protected]> wrote:
> > I've looked through the user documentation but did not find a clue to
> > this problem. I have not dug too deeply into the code.
> >
> > The problem is to safely re-initialize a running fuseki server to read a
> > new tdb location.
> >
> > I've thought of using 2 (or more) jetty or tomcat workers in a
> > load-balancing configuration, which would allow staged restarts. But
> > before I go there I thought I would ask if there is an easier way.
> >
> > Does anyone have a usage pattern for this, or can point me to some
> > documentation or classes that would get me started?
> >
> > Thanks,
> > --Paul
> >
> 
> 
> 


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