we are updating our SOLR infrastructure from version 4.10.2 to the latest 6.6.
We realize a significant degradation of the response time while running
match-all queries with facets (query in ) With version 4.x these kind of
queries never took longer than 2000 ms.
Now all of these queries need more than 9000 ms.
Our index   contains around 30 Mio docs. Because we want to use
doc-values for facets and sort functions we changed our doc-processing
significantly replacing all text type with string fields.
The behavior of normal term queries is acceptable although it's a little bit
slower compared with the current productive environment. Yesterday I run a
couple of performance tests
I looked around and came across this (older) issue  which is partially
related to our observations but actually I cannot find a solution for our
Did we miss something on the way of the development from version 4 / 5 / 6
which might be the reason for the degradation and we should change our queries?
Thanks a lot for any hints