MySQL — InnoDB vs. MyISAM
TL;DR
| feat | InnoDB | MyISAM |
| Locking Mechanism | row/record level | table level |
| Transaction Support | ACID compliant | No transaction support |
| Foreign Keys | ✅ | ❌ |
| Crash Recovery | auto | manual |
| Buffer | Buffer pool for data & index | Key buffer for index only |
| Performance Focus | Write-intensive workloads | Read-intensive workloads |
| Fit for | High concurrency, write-intensive needs; ideal for new projects | Large-scale read operations; suitable for projects with existing large datasets |
Choose InnoDB when
- You need transaction support
- High concurrency for both read/write
- Foreign key constraints required
- Automatic crash recovery important
- lock on specific row/record.
For example, update and insert operations:
BEGIN;
UPDATE inventory SET quantity = quantity - 1 WHERE item_id = 5;
INSERT INTO orders (item_id, user_id) VALUES (5, 101);
COMMIT;
Choose MyISAM when
- Read-heavy workloads
- Simple data structures
- Full-text indexing needed (in older MySQL versions)
- Server resources are limited
- lock whole table
For example, simple aggregation queries:
SELECT category, COUNT(*)
FROM log_entries
GROUP BY category;
Just like SSD and HDD
MyISAM does not restrict sequential or non-sequential reads, which can be advantageous for read-heavy operations. However, in scenarios with frequent write and update operations, MyISAM's performance may degrade, similar to how an HDD struggles with non-sequential reads when data becomes fragmented.
InnoDB uses a clustered index which keeps related data close together. This can improve performance for both sequential and non-sequential operations, especially in write-intensive scenarios.
https://stackoverflow.com/questions/15678406/when-to-use-myisam-and-innodb