Storage Engine
Supported Storage Engines
InnoDB
- 具有事務安全性（ACID Compliant）。
- 使用行級鎖，且支援類似於 Oracle 的一致性非鎖定讀取，提高了多用戶並發效能。
- 將資料儲存在 clustered index，以減少基於 PK 查詢的 I/O。
MyISAM
- 使用表級鎖，Use Case 有：
- Log Table
Feature Summary
| Feature | MyISAM | Memory | InnoDB | Archive | NDB |
|---|---|---|---|---|---|
| B-tree indexes | Yes | Yes | Yes | No | No |
| Backup/point-in-time recovery (note 1) | Yes | Yes | Yes | Yes | Yes |
| Cluster database support | No | No | No | No | Yes |
| Clustered indexes | No | No | Yes | No | No |
| Compressed data | Yes (note 2) | No | Yes | Yes | No |
| Data caches | No | N/A | Yes | No | Yes |
| Encrypted data | Yes (note 3) | Yes (note 3) | Yes (note 4) | Yes (note 3) | Yes (note 5) |
| Foreign key support | No | No | Yes | No | Yes |
| Full-text search indexes | Yes | No | Yes (note 6) | No | No |
| Geospatial data type support | Yes | No | Yes | Yes | Yes |
| Geospatial indexing support | Yes | No | Yes (note 7) | No | No |
| Hash indexes | No | Yes | No (note 8) | No | Yes |
| Index caches | Yes | N/A | Yes | No | Yes |
| Locking granularity | Table | Table | Row | Row | Row |
| MVCC | No | No | Yes | No | No |
| Replication support (note 1) | Yes | Limited | Yes | Yes | Yes |
| Storage limits | 256TB | RAM | 64TB | None | 384EB |
| T-tree indexes | No | No | No | No | Yes |
| Transactions | No | No | Yes | No | Yes |
| Update statistics for data dictionary | Yes | Yes | Yes | Yes | Yes |
Note
1. Implemented in the server, rather than in the storage engine.
2. Compressed MyISAM tables are supported only when using the compressed row format. Tables using the compressed row format with MyISAM are read only.
3. Implemented in the server via encryption functions.
4. Implemented in the server via encryption functions; In MySQL 5.7 and later, data-at-rest encryption is supported.
5. Implemented in the server via encryption functions; encrypted NDB backups as of NDB 8.0.22; transparent NDB file system encryption supported in NDB 8.0.29 and later.
6. Support for FULLTEXT indexes is available in MySQL 5.6 and later.
7. Support for geospatial indexing is available in MySQL 5.7 and later.
8. InnoDB utilizes hash indexes internally for its Adaptive Hash Index feature.