You are able to use Odysseus Script to parallelize an created script automatically. To use this functionality Odysseus Script provides two keywords.

#PARALLELIZATION

This keyword tells Odysseus, that the given query needs to be parallelized. There are two parameters that are mandatory and one optional parameter. 

 

The following example shows the usage of this keyword. This example uses the inter-operator parallelization with an degree of 4 and an automatic buffersize.

#PARSER PQL
#PARALLELIZATION INTER_OPERATOR 4 AUTO
#RUNQUERY
windowBid = TIMEWINDOW({SIZE = [1, 'MINUTES'],
                  advance = [1, 'SECONDS']
                  }, bid)

windowAuction = TIMEWINDOW({SIZE = [10, 'MINUTES'],
                  advance = [1, 'SECONDS']
                  }, auction)

join = JOIN({PREDICATE = 'bid.bidder == auction.id'}, windowBid, windowAuction)

If this keyword is used, every operator of the query, which has an compatible parallelization strategy is transformed. If only a one are a few operators should parallelized the following keyword need to be used in addition.

 

#INTEROPERATORPARALLELIZATION

The #INTEROPERATORPARALLELIZATION keyword is an addition to the #PARALLELIZATION keyword for inter-operator parallelization. With this keyword it is possible to select one or more operators, which should be parallelized. The is also the possibility to configure the parallelization for each operator. This keyword provides some parameters:

 

The following code example shows the usage of this keyword. Only the aggregation is parallelized, because only this id is defined. The global parallelization degree is overwritten with the value of 2. With the constant GLOBAL the value for the buffersize is used from the global definition. In addition to this parameters, also the parallelization strategy is defined manually. In this case the AggregateMultithreadedTransformationStrategy is used. Note that the strategy need to be fit to the operator type defined with the id. In addition the strategy need to be compatible for the operator. In some cases it is not possible to use the selected strategy, e.g. an Grouping inside the aggregation is needed. The last parameter in this example is the optional selection of an fragmentation type. Note that also on this point not every strategy supports all fragmentation types. See the list below for all possible combinations.

#PARSER PQL
#PARALLELIZATION INTER_OPERATOR 4 AUTO
#INTEROPERATORPARALLELIZATION aggregateId 2 GLOBAL AggregateMultithreadedTransformationStrategy ShuffleFragmentAO
#RUNQUERY

windowBid = TIMEWINDOW({SIZE = [1, 'MINUTES'],
                  advance = [1, 'SECONDS']
                  }, bid)

windowAuction = TIMEWINDOW({SIZE = [10, 'MINUTES'],
                  advance = [1, 'SECONDS']
                  }, auction)

join = JOIN({ID = 'joinId', PREDICATE = 'bid.bidder == auction.id'}, windowBid, windowAuction)

sum_price_bidder = AGGREGATE({ID = 'aggregateId',
                              aggregations = [
                                ['SUM', 'price', 'sum_price_bidder']
                              ],
                              FASTGROUPING = true                                                                    
                            },
                            join
                          )

Strategies and supported fragmentation types

Logical operatorParallelization strategiesDescriptionSupported fragmentation types
JoinAO

JoinMultithreadedTransformationStrategy

Uses an Hash-Fragmentation for both input streams. The fragmentation attributes are gathered from the join attributes. Note that only equals-predicates (which are concatenated with &&) are supported. The fragmented datastream is merged with an UNION Operator.

HashFragmentAO

AggregateAO

AggregateMultithreadedTransformationStrategy

 

Uses an RoundRobin or Shuffle Fragmentation for split of the input datastream. This strategy works with partial aggregates and merges the datastream both with an union operator and an additional aggregate operator for merging the partial aggregates. This strategy works with and without grouping. Only aggregations with one input attribute are supported.RoundRobinFragmentAO

ShuffleFragmentAO

GroupedAggregateMultithreadedTransformationStrategy

Uses a Hash-Fragmentation for the input stream. The fragmentation attributes are gathered from the grouping attributes. So this strategy only works if the aggregate operator has an grouping. The fragmented datastream is merged with an UNION Operator.

HashFragmentAO

Bold fragmentation types shows the preferred type if nothing is defined.