Music Index Bitmap System MIBS

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Music Index Bitmap System (MIBS)

• Detail Level Design
• -By MIBS development team

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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

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Bitmap Encoding
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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

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Bitmap compression

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

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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

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Steps in WAH compression
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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

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Questions??

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