A Ssignment P Roblems of D Ifferent - S Ized

نویسندگان

  • Shlomi Dolev
  • Ephraim Korach
  • Shantanu Sharma
  • Jeffrey D. Ullman
  • Foto Afrati
چکیده

A MapReduce algorithm can be described by a mapping schema, which assigns inputs to a set of reducers, such that for each required output there exists a reducer that receives all the inputs that participate in the computation of this output. Reducers have a capacity, which limits the sets of inputs that they can be assigned. However, individual inputs may vary in terms of size. We consider, for the first time, mapping schemas where input sizes are part of the considerations and restrictions. One of the significant parameters to optimize in any MapReduce job is communication cost between the map and reduce phases. The communication cost can be optimized by minimizing the number of copies of inputs sent to the reducers. The communication cost is closely related to the number of reducers of constrained capacity that are used to accommodate appropriately the inputs, so that the requirement of how the inputs must meet in a reducer is satisfied. In this work, we consider a family of problems where it is required that each input meets with each other input in at least one reducer. We also consider a slightly different family of problems in which, each input of a set, X , is required to meet each input of another set, Y , in at least one reducer. We prove that finding an optimal mapping schema for these families of problem is NP-hard, and present a bin-packing-based approximation algorithm for finding a near optimal mapping schema.

برای دانلود رایگان متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

منابع مشابه

Genetics and the epidemiology of leprosy. II. The form of leprosy.

Leprosy is made manifest i n a variety of forms and the classifica­ tion and relat ionships of these forms are matters of controversy . There is , however, wide agreement that communit ies vary i n the relative frequencies of the d ifferent forms of the d i sease and, further­ more, it i s accepted that the symptoms with in a part icular form of the d isease may vary i n d ifferent populations....

متن کامل

Photophosphorylation as Function of ADP Concentration at Varying Transmembrane Proton Gradients

R ates o f pho tophosphory lation were m easured at constant sa tu rating phosphate concen tra tion , varying A D P concen tra tion , and varying light intensity. As the transm em brane p ro ton grad ien t is d ecreased by phosphoryla tion to d ifferent extents depending on the concentra tion o f A D P . rates o f A T P form ation ob tained at the d ifferent A D P concentrations w ere p lo tted...

متن کامل

C Omparison of D Ifferent B Roadcast S Chemes for M Ulti

In this paper, we present the performance of different broadcast schemes for multihop sensor networks based on mathematical modeling. In near future many applications will demand multicast (Broadcast) communication feature from the sensor networks. This broadcast feature does not use virtual carrier sensing but relies on physical carrier sensing to reduce collision. For this paper, we analyze t...

متن کامل

ذخیره در منابع من


  با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید

عنوان ژورنال:

دوره   شماره 

صفحات  -

تاریخ انتشار 2014