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Parallelization Settings


OntoBroker can use multiple CPUs for processing executing server commands, for loading ontologies, and for parallelizing evaluation of a query. Each of these three areas can be configured separately using configuration switches.

Parallelize.ServerCommands = <on | off>  

If this switch is on, OntoBroker can process multiple server commands (e.g. queries) from clients at the same time.

Parallelize.ServerCommands.MaxThreads = <integer|auto>

This switch determines the maximum number of threads used for parallelizing server commands (only if Parallelize.ServerCommands = on). The default value is "auto", i.e. automatic configuration depending on the number of available CPUs (cores).

Parallelize.Loader = <on | off>  

This switch controls the loading of multiple ontologies. If it is turned on, OntoBroker can load multiple ontology files on a parallel basis. For persistent storages (e.g. H2), this feature is always turned off automatically, as it has a negative impact on performance.

Parallelize.Loader.MaxThreads = <integer|auto>

This switch sets the maximum number of threads used for loading ontology files.

Parallelize.Reasoner = on | off    

This switch controls the evaluation of queries. If it is turned on, the evaluation of a query may be distributed on multiple threads wherever possible.

Parallelize.Reasoner.MaxThreads = <integer|auto>  

This switch determines the overall number of threads available for executing query evaluation tasks.

Parallelize.Reasoner.Connectors.MaxThreads = <integer|auto>

This switch determines how many threads are available for connectors. Every connector call is processed in a seperate thread. As connectors communicate with external resources, this switch controls the load OntoBroker can produce on these resources.

Some evaluation methods support two types of parallelization: operatornet parallelization (this is the OntoConfig switch "Parallelize.Reasoner") and join-level parallelization. For the latter there is now an explicit switch.

Parallelize.Joins = on | off Parallelize.Joins.MaxThreads = <integer> | auto