- default in 5.1 or older
- main features:
- full-text indexing
- compression
- GIS spacial functions
- does NOT have transactions or row-level locking
- typically stores data in 2 files – data file, index file
- tables can have rows both with fixed or dynamic length
- size of table is limited by OS
- locks:
- locks entire table
- concurrency inserts allow to add new row even when there is shared read lock on table
- table repair:
- commands CHECK TABLE and REPAIR TABLE – simply deletes corrupted data from table
- if server is offline we can use also “myisamchk” command line tool
- indexes:
- up to first 500 characters on BLOB or TEXT
- delayed key writes – indexes are updated only in memory and flushed to disk only during buffer prune – if server crashes then index must be repaired
- data compression:
- we cannot modify compressed tables – therefore usable for huge read-only data
- helps reduce I/O, overhead on CPU is unsignificant