Do you always need index on WHERE column ? | MySQL Performance Blog - The Diigo Meta page

• 27 Mar 11
  

  s_m_roberts

  mysql php performance index database

• 21 Mar 11
  

  Esen Sagynov

  sql index

• 01 May 08
  

  Renato Albano

  mysql database optimization sql performance index programming

• 16 Apr 08
  

  Navneet Kumar

  The reason why index scan is slower than table scan is that in case of the index scan the MySQL needs to perform more operations like :
  read index, get pointer to row, get data from row,
  that adds overhead to the operations.
  Full table scan takes constant time no matter the cardinality, index traversing speed depends on the index cardinality

  MySQL Index Performance

  • The reason why index scan is slower than table scan is that in case of the index scan the MySQL needs to perform more operations like :
     read index, get pointer to row, get data from row,
     that adds overhead to the operations
  • Full table scan takes constant time no matter the cardinality, index traversing speed depends on the index cardinality
  • hy index scan is
  • perations like :
     read index, get pointer to row
  • Full table scan takes constant time no matter the cardinality, index traversing speed depends on the index cardinality.
  • The reason why index scan is slower than table scan is that in case of the index scan the MySQL needs to perform more operations like :
     read index, get pointer to row, get data from row,
     that adds overhead to the operations.

  4 more annotations...

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