Overview

Module riak_mapred_query

• Description
• Data Types
• Function Index
• Function Details

Description

driver for mapreduce query. Map phases are expected to have inputs of the form [{Bucket,Key}] or [{{Bucket,Key},KeyData}] (the first form is equivalent to [{{Bucket,Key},undefined}]) and will execute with locality to each key and must return a list that is valid input to the next phase

Reduce phases take any list, but the function must be commutative and associative, and the next phase will block until the reduce phase is entirely done, and the reduce fun must return a list that is valid input to the next phase

• {link, Bucket, Tag, Acc}
• {map, FunTerm, Arg, Acc}
• {reduce, FunTerm, Arg, Acc}

• {modfun, Mod, Fun} : Mod and Fun both atoms -> Mod:Fun(Object,KeyData,Arg)
• {qfun, Fun} : Fun is an actual fun -> Fun(Object,KeyData,Arg)

Data Types

mapred_funterm()

mapred_funterm() = {modfun, Module::atom(), Function::atom()} | {qfun, function()}

mapred_queryterm()

mapred_queryterm() = {map, mapred_funterm(), Arg::term(), Accumulate::boolean()} | {reduce, mapred_funterm(), Arg::term(), Accumulate::boolean()} | {link, Bucket::riak_object:bucket(), Tag::term(), Accumulate::boolean()}

mapred_result()

mapred_result() = [term()]

Function Index

Function Details

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Overview

Generated by EDoc, Mar 10 2010, 09:21:17.