• very similar to MyISAM
  • engine creates tables only in memory, no I/O operations are done
  • usefull for:
    • masivelly used config data, list of values etc.
    • caching results from periodical queries
    • intermediate results from data analysis
  • has HASH indexes
  • table locking
  • only fixed size row, no BLOB or TEXT columns
  • used internally by MySQL for temporary and intermediate results