Graefe, Goetz, “Encapsulation of Parallelism in the Volcano Query Processing System ; CU-CS” (). Computer Science Technical Reports. Encapsulation of parallelism in the volcano query processing system – Graefe ‘ You may have picked up on the throwaway line in the Impala. Encapsulation of Parallelism in the Volcano Query Processing System (). The Volcano query processing system uses the operator model of query.

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The uniform interface between operators makes Volcano extensible by new operators.

Encapsulation of parallelism in the Volcano query processing system

The exchange operator in the consumer process acts as a normal iterator, the only difference from other iterators is that it receives its input via inter-process communication. You are commenting using your Twitter account. The exchange operator can be used to implement pipelined parallelism called vertical parallelism in the paperbushy parallelism processing different parallellsm of a complex query tree in paralleland intra-operator parallelism partitioning the dataset and processing partitions in parallel for a single operator.

When the exchange operator is opened, it does not fork any processes but establishes a communication port for data exchange.

Parallel computing Dataflow Parallel database. Citation Statistics Citations 0 10 20 30 ’90 ’96 ’03 ’10 ‘ When attempting to parallelize Volcano, we had to choose between two models of parallelization, called here the bracket and operator models.


“Encapsulation of Parallelism in the Volcano Query Processing System ; ” by Goetz Graefe

An operator does not need to know what kind of operator produces its input, and whether its input comes from a complex query or from a simple file scan. HellersteinEric A. This removes some communication overhead. Enterprise Database Applications and the Cloud: Notice that it is an iterator with open, next, and close procedures; therefore, it can be inserted at any one place or at multiple places in a complex query tree. When the query tree is opened the first process is the master.

Showing of extracted citations. A process runs a producer and produces input for the other processign only if it does not have input volcao the consumer.

Given this, the way that Volcano introduces parallelism is very simple: The key benefit of the exchange operator technique is that is allows query processing algorithms to be coded for single-process execution but run in a highly parallel environment without modifications.

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You are commenting using your Iin account. The next operation requests records from its input tree, possibly sending them off to other processes in the group, until a record for its own partition is found.


Sorry, your blog cannot share posts by email. By clicking accept or continuing to use the site, you agree to the terms outlined in our Privacy PolicyTerms of Serviceand Dataset License. An iterator can hold internal state, so that one algorithm operator can be used multiple times in a query.


It includes an exchange operator that allows intra-operator parallelism on partitioned datasets and both vertical and horizontal inter-operator parallelism. Notify me of new posts via email. For intra-operator parallelism a process group operates on partitions in parallel. You are commenting using your WordPress. This mode of operation also makes flow control obsolete. Encapsulation networking Systems theory Process architecture.

systm Every operator is implemented as an iterator per Hellerstein et al: From This Paper Topics from this paper. Post was not sent – check your email addresses! Citations Publications citing this paper. Subscribe never miss an issue! See our FAQ for additional information. A uniform interface between operators, e. ShahJoseph M. The iterators support a simple open-next-close protocol.