Exception:virtuoso.jdbc4.VirtuosoException: SQ186: Over 20 keys in group by or hash join

Hi there,

is there any parameter to be set in “virtuoso.ini” to accommodate the limitation in subject?
I’m on image 7.2.6-r2-gf5e32aa.


There are no INI file params to avoid such errors. In what context this error occurring, do you have a reproducible test case or query that produces the error etc ?

I have published a simplified query in here: https://gist.github.com/michimau/0380ebc00116d6ef13b0d7c1c991fe8c

It will run on http://cr.eionet.europa.eu/sparql (6.1.8 custom docker image)
it will fail on http://cr7.eionet.europa.eu/sparql (7.2.6-r2-gf5e32aa official)

Looks like the group_concat_distinct is causing the error as the query runs if it is removed. So looking into how it can be avoided …

This is just an example where group_concat_distinct is not even needed. But in principle it should not fail: it looks like some default settings on join hash are pretty conservative in 7.x.x, as the query works fine on 6.1.8.