Differences between MySQL storage engine MyISAM and InnoDB

1.MyISAM Storage engine

MyISAM Engine features

• Unsupported transaction
• Table level locking
• Reading and writing block each other , Write cannot read , You can't write when you read
• Cache index only
• Foreign key constraints are not supported
• Clustered index is not supported
• Read data faster , Less resources
• I won't support it MVCC（ Multi version concurrency control mechanism ） High concurrency
• Crash recovery is poor
• MySQL5.5.5 The default database engine before

MyISAM Storage engine application scenarios

• read-only （ Or write less ）
• Small table （ Long time repair operation is acceptable ）

MyISAM Engine files

• tbl_name.frm Table format definition
• tbl_name.MYD Data files
• tbl_name.MYI Index file

2.InnoDB engine

InnoDB Engine features

• Row-level locks
• Support transactions , Suitable for dealing with a large number of short-term Affairs
• Read and write blocking is related to transaction isolation level
• Cacheable data and indexes
• Support clustering index
• Crash resilience is better
• Support MVCC High concurrency
• from MySQL5.5 Full text index is supported after
• from MySQL5.5.5 Start with the default database engine

InnoDB Database files

• all InnoDB The data and index of the table are placed in the same tablespace

Data files ：ibdata1, ibdata2, Store in datadir Defined directory

Table format definition ：tb_name.frm, Store in datadir Define the corresponding directory of each database

• Each form uses a single table space to store the data and index of the table

  The two types of files are placed in a separate directory corresponding to each database

Data files ( Store data and index )：tb_name.ibd

Table format definition ：tb_name.frm