None is generally a really bad idea.  You have to hand optimize every query.

Note that there are some problems with BIND().  Check the tickets and you will see that this is not optimized correctly for many cases.  Maybe this is the problem?


From: feugen24 <>
Reply-To: "[bigdata:discussion]" <>
Date: Tuesday, March 18, 2014 9:48 AM
To: "[bigdata:discussion]" <>
Subject: [bigdata:discussion] Bigdata query optimizer

While testing various scenarios I loaded db with ~7M triples and I noticed the default static optimizer fails in simple scenarios, meaning that it rearranges the query so it joins much more than needed.
For example given a inner query that binds a ?s variable to 3 values, if i want to get all triples for ?s (~ 10 triples) and I join with ?s ?p ?o, it takes few minutes to get them (and 2G of ram), but with optimizer set to "None" or "Runtime" it's just few ms as it should.

If someone is evaluating the db he will get the impression of poor performance. Also I tried to find a config setting that changes the default optimizer since now I have to set it to None in all queries.
So can I set a default?
In general the performance should be better with static optimizer so i should try to use it?
In this kind of situations a bug should be reported? (I have the impression the query is v simple so it should work fine with any optimizer)


Bigdata query optimizer

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