Thanks for the update. Maybe this is a good opportunity to say that you
and everybody involved in WDQS are doing a tremendous job in maintaining
this service. Even with the small glitches in the last week, this is
still one of the most reliable public SPARQL endpoints that I have seen.
This is not a small achievement, considering how the load is
continuously shifting and changing (e.g., if someone announces a tool
that queries the hitherto neglected "GAS Service" every time that a user
clicks on the link!). And on top of all this, we are getting some very
quick email responses here whenever there is an issue (or even just a
usage question). So thanks for all the efforts -- this is an absolutely
crucial piece of infrastructure, and it is good to see it in such
On 04.02.2016 22:10, Stas Malyshev wrote:
As it was noted on the list, we recently tried to update Blazegraph -
software running Wikidata Query Service - to version 2.0, which has
numerous bugfixes and performance improvements, and some infrastructure
for future work on Geospatial search, etc.
Unfortunately, it seems, as it sometimes happens with new major
releases, that there are certain bugs in it, and yet more unfortunately,
one of the bugs seems to be of a race condition nature, which is very
hard to trigger on test environment, and that, when triggered, seriously
impacts the stability of the service. All this lead to WDQS service
being somewhat unstable last couple of days.
Due to this, I have rolled the production deployment back to pre-2.0
state. This means the service should be stable again and not experience
glitches anymore. I'll be watching it just in case and if you notice
anything that looks broken (like queries producing weird exceptions -
timeout does not count - or service being down, etc.) please ping me.
In the meantime, we will look for the cause of instability, and once it
is identified and fixed, we'll try the Blazegraph 2.0 roll-out again,
with the fixes applied. I'll send a note to the list when it happens.
Faculty of Computer Science
Technische Universität Dresden
+49 351 463 38486