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From Apache Wiki <wikidi...@apache.org>
Subject [Hadoop Wiki] Update of "Hamburg" by edwardyoon
Date Thu, 02 Jul 2009 06:56:18 GMT
Dear Wiki user,

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The following page has been changed by edwardyoon:

The comment on the change is:
become a proposal.

  ## page was renamed from Hambrug
+ == Motivation ==
+ The MapReduce (M/R) programming model is inappropriate to problems based on data where each
portion depends on many other potions and their relations are very complicated. It is because
these problems cause as follows:
+  * limit to assigning one reducer
+   * In case that the relations of data are very complex, assigning intermediate data to
appropriate reducers by considering their dependency of partitioned graphs may be very hard.
Assigning only one reducer is a straightway to solve complexity dependency, but it is apparent
to cause deterioration of scalability.
+  * many M/R iterations
+  * or make an M/R program more complicated
+   * To avoid above two inefficient methods, the M/R program will be complicated with code
to communicate data among data nodes.
+ These problems are very common in many areas; especially, many graph problems are exemplary.

+ TODO - write description of an example.
+ Therefore, we try to propose a new programming model, named Hamburg. The main objective
of Hamburg is to support well the problems based on data having complexity dependency one
another. This page is an initial work of our proposal.
+ == Goal ==
+  * Follow scalability concept of shared-nothing architecture
+  * Support a simple programming model to compute complex relations such as, graph data.
  == Hamburg ==
- Let's discuss about the graph computing framework named Hamburg.
+ Hambrug is an alternative to M/R programming model. It is based on bulk synchronization
parallel (BSP) model. Like M/R, Hambrug takes advantages from shared-nothing architecture
(SN), so I expect that it will also show scalablity without almost degradation of performance
as the number of participant nodes increases.
+ A Hamburg based on BSP computation step consists of three sub steps:
+  * Computation on data that reside in local storage; it is similar to map operation in M/R.
+  * Each node communicates its necessary data into one another.
+  * All processors synchronize which waits for all of the communications actions to complete.
+ The main difference between Hamburg and M/R is that Hamburg does not make intermediate data
aggregate into reducer. Instead, each computation node communicates only necessary data into
one another. 
+ It will be efficient if total communicated data is smaller then intermediate data to be
aggregated into reducers.
+ === Initial contributors ===
- ----
- If you want to talk directly with us,
   * Edward J. (edwardyoon AT apache.org)
   * Hyunsik Choi (hyunsik.choi AT gmail.com)
+ Any volunteers are welcome.
  == Related Projects ==

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