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Multiple Query Optimization

Posted: Sun Jan 18, 2015 5:01 am
by Alireza
Hello,

I got two questions:
1) Is there is any documentation about the multi-layer optimization strategies that Odysseus perform?
2) Does Odysseus show the different Query execution plans with their associated cost as we have in DBMSs (like SQL Server or Oracle)?

Thank you very much,
Alireza

Re: Multiple Query Optimization

Posted: Mon Jan 19, 2015 10:29 am
by Marco Grawunder
1) Not really. Currently, Odysseus performs the following to optimizations:
a) Query rewrite: e.g. Selection and projection pushdown
b) Query sharing: Along as the way from the sources to the sinks are the same in different queries, only one operator for each query is used.
2) Currently, different execution plans are not generated. It is not that necessary in stream system because we do not have mulitple data access paths to choose from. Only join order could be relevant, but for this meta data about the sources is needed. There are first approaches but not in the current release.

Re: Multiple Query Optimization

Posted: Fri Jan 23, 2015 5:39 am
by Alireza
Thank you very much for the information.