Mysql search engine and its differences

Generally used engines for MySQL are: ISAM, MyISAM, HEAP, InnoDB and Berkley (BDB).

ISAM: ISAM performs read operations very quickly and does not occupy a lot of memory and storage resources. , the shortcomings are: it does not support transactions, does not support foreign keys, and is not fault-tolerant.

MyISAM: Based on ISAM, it provides a large number of index and field management functions that ISAM does not have. It also uses a table locking mechanism to optimize multiple concurrent read and write operations, but it is a waste of space. , you need to run the command (OPTIMIZE TABLE) to recover the space wasted by the update mechanism.

HEAP: Allows temporary tables to reside only in memory. Memory-resident makes it faster than ISAM and MyISAM, but the data it manages is also unstable. If it is not saved before shutting down, All data will be lost. HEAP will not waste a lot of space when data is deleted. HEAP tables are very useful when you need to use SELECT expressions to select and manipulate data. But remember, delete the form after you are done with it!

InnoDB and BDB: Although much slower than the ISAM and MyISAM engines, they include support for transaction processing and foreign keys.

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