Music Index Bitmap System MIBS - PowerPoint PPT Presentation

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Music Index Bitmap System MIBS

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Byte aligned bitmap code (BBC) Word aligned Hybrid (WAH) 5. Music Index Bitmap System (MIBS) ... BBC vs WAH. Both are based on run-length encoding. BBC stores ... – PowerPoint PPT presentation

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Tags: mibs | bbc | bitmap | index | music | system

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Transcript and Presenter's Notes

Title: Music Index Bitmap System MIBS


1
Music Index Bitmap System (MIBS)
  • Detail Level Design
  • -By MIBS development team

2
Bitmap Index
  • Based on bitmaps a vector of bits
  • Basic data structure applied to query
    optimization in data warehouses
  • Different bitmap encoding techniques
  • Equality
  • Range
  • Interval
  • Bit-sliced

3
Bitmap Encoding
4
Query Execution
  • Logical bitwise operations (AND,OR,NOT)
  • For equality encoded bitmaps AND together bit
    values for attributes (point queries)
  • For range queries first OR then AND the answers
    together

5
Bitmap compression
  • Needs compression
  • Most popular techniques are
  • Byte aligned bitmap code (BBC)
  • Word aligned Hybrid (WAH)

6
BBC vs WAH
  • Both are based on run-length encoding
  • BBC stores the compressed data in bytes while WAH
    stores it in words
  • BBC compresses better than WAH
  • But WAH is more CPU-friendly than BBC

7
Steps in WAH compression
8
Optimality of WAH
  • At most 2N words are required
  • In general, to answer a query using bitmaps at
    most half of the index is required
  • So in case of WAH at most N words

9
Questions??
  • Contact us
  • Chris (reiner.18_at_osu.edu)
  • Yogesh (pendharkar.1_at_osu.edu)
  • Greg (forrest.63_at_osu.edu)
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