Nothing specifically known.
In SDB, UNIONs are not done in the SQL database,. They are the
concatenation of each subpart. if that's combined with an earlier
pattern that is joined to the union, there can be a lot of calls to the
database, each with JDBC latency overhead.
Again, something that works a whole lot better in TDB.
Andy
On 06/06/11 15:36, Simon Helsen wrote:
Hi,
I am currently doing experiments to evaluate SDB in terms of performance
and scalability. I noticed that queries with a large number of UNIONs do
not behave well (meaning, taking more than a minute on a small store). Are
there known problems with these kind of queries? I am still on SDB 1.3.2
thanks,
Simon
