Database System Concepts
Database System Concepts
7th Edition
ISBN: 9780078022159
Author: Abraham Silberschatz Professor, Henry F. Korth, S. Sudarshan
Publisher: McGraw-Hill Education
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Chapter 15, Problem 15PE

Explanation of Solution

Nested-loops join algorithm poorly works on database:

  • With the column oriented storage, every attributes of the relation is stored in a different file...

Explanation of Solution

Alternative algorithm for better usage:

  • Join queries are not fast with column oriented storage as joins involving reading many columns of many records and large amount of data has to be read from the two relations.
  • The invisible join algorithm is designed for column oriented data warehouses organized in a star schema.
  • Here, join one fact table with many dimensions table thereby making sure that the table that can be accessed in position order is the fact table for each join.
  • Now, insert the position lists from the fact table in position order thereby reducing the amount of data accessed out of order from the dimensions table.
  • Next, rewrite the joins into selection predicates on the foreign key column in the fact table...

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