Home / cs-notes / Architecture / Components / Database / MySQL / Index / B+ Tree Index

• Balance Tree

• Operation

  • Deep Search
    • break balance
    • tree node split
    • tree node re-merge

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Compare with Red-Black Tree

• less search
  • bigger out degree
    • more children in one node
  • smaller tree height
• use disk pre-read ordered reading
  • less IO operation
  • less disk track switching

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Primary Index

• unique each table
• save data in data field

Secondary Index

• save primary key in data field

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