InnoDB offers:

ACID transactions
row-level locking
foreign key constraints
automatic crash recovery
table compression (read/write)
spatial data types (no spatial indexes)

在InnoDB中，一行中除TEXT和BLOB外的所有数据最多占用8000字节。InnoDB没有全文索引。在InnoDB中，COUNT(*)s(当WHERE, GROUP BY或JOIN不使用时)执行速度比MyISAM慢，因为行数没有存储在内部。InnoDB将数据和索引存储在一个文件中。InnoDB使用缓冲池来缓存数据和索引。

MyISAM提供：

fast COUNT(*)s (when WHERE, GROUP BY, or JOIN is not used)
full text indexing
smaller disk footprint
very high table compression (read only)
spatial data types and indexes (R-tree)

MyISAM has table-level locking, but no row-level locking. No transactions. No automatic crash recovery, but it does offer repair table functionality. No foreign key constraints. MyISAM tables are generally more compact in size on disk when compared to InnoDB tables. MyISAM tables could be further highly reduced in size by compressing with myisampack if needed, but become read-only. MyISAM stores indexes in one file and data in another. MyISAM uses key buffers for caching indexes and leaves the data caching management to the operating system.

总的来说，我推荐InnoDB用于大多数用途，MyISAM仅用于特殊用途。InnoDB现在是MySQL新版本的默认引擎。

有点偏离主题，但为了文档的目的和完整性，我想添加以下内容。

一般来说，使用InnoDB会使应用程序变得不那么复杂，可能也更没有bug。因为可以将所有引用完整性(外键约束)放入数据模型中，所以不需要像使用MyISAM时那样多的应用程序代码。

Every time you insert, delete or replace a record, you will HAVE to check and maintain the relationships. E.g. if you delete a parent, all children should be deleted too. For instance, even in a simple blogging system, if you delete a blogposting record, you will have to delete the comment records, the likes, etc. In InnoDB this is done automatically by the database engine (if you specified the contraints in the model) and requires no application code. In MyISAM this will have to be coded into the application, which is very difficult in web-servers. Web-servers are by nature very concurrent / parallel and because these actions should be atomical and MyISAM supports no real transactions, using MyISAM for web-servers is risky / error-prone.

而且在大多数情况下，InnoDB会表现得更好，原因有很多，其中一个原因是它能够使用记录级锁而不是表级锁。不仅在写比读更频繁的情况下，在大型数据集上有复杂连接的情况下也是如此。我们注意到，对于非常大的连接(需要几分钟)，使用InnoDB表比MyISAM表性能提高了3倍。

我想说的是，在使用MySQL时，InnoDB(使用3NF数据模型，具有引用完整性)应该是默认的选择。MyISAM只能在非常具体的情况下使用。它很可能会执行更少，导致应用程序更大，bug更多。

话虽如此。数据模型是一门很少在网页设计师/程序员中发现的艺术。无意冒犯，但这确实解释了MyISAM被如此广泛使用的原因。

人们经常谈论性能、读写、外键等等，但在我看来，存储引擎还有一个必须具备的特性:原子更新。

试试这个:

Issue an UPDATE against your MyISAM table that takes 5 seconds. While the UPDATE is in progress, say 2.5 seconds in, hit Ctrl-C to interrupt it. Observe the effects on the table. How many rows were updated? How many were not updated? Is the table even readable, or was it corrupted when you hit Ctrl-C? Try the same experiment with UPDATE against an InnoDB table, interrupting the query in progress. Observe the InnoDB table. Zero rows were updated. InnoDB has assured you have atomic updates, and if the full update could not be committed, it rolls back the whole change. Also, the table is not corrupt. This works even if you use killall -9 mysqld to simulate a crash.

性能当然是可取的，但不丢失数据更重要。

InnoDB offers:

ACID transactions
row-level locking
foreign key constraints
automatic crash recovery
table compression (read/write)
spatial data types (no spatial indexes)

在InnoDB中，一行中除TEXT和BLOB外的所有数据最多占用8000字节。InnoDB没有全文索引。在InnoDB中，COUNT(*)s(当WHERE, GROUP BY或JOIN不使用时)执行速度比MyISAM慢，因为行数没有存储在内部。InnoDB将数据和索引存储在一个文件中。InnoDB使用缓冲池来缓存数据和索引。

MyISAM提供：

fast COUNT(*)s (when WHERE, GROUP BY, or JOIN is not used)
full text indexing
smaller disk footprint
very high table compression (read only)
spatial data types and indexes (R-tree)

MyISAM has table-level locking, but no row-level locking. No transactions. No automatic crash recovery, but it does offer repair table functionality. No foreign key constraints. MyISAM tables are generally more compact in size on disk when compared to InnoDB tables. MyISAM tables could be further highly reduced in size by compressing with myisampack if needed, but become read-only. MyISAM stores indexes in one file and data in another. MyISAM uses key buffers for caching indexes and leaves the data caching management to the operating system.

总的来说，我推荐InnoDB用于大多数用途，MyISAM仅用于特殊用途。InnoDB现在是MySQL新版本的默认引擎。

我不是数据库专家，也不是凭经验说的。然而:

MyISAM表使用表级锁定。根据您的流量估计，您每秒有接近200个写入操作。有了MyISAM，在任何时候只有其中一项可以进行。您必须确保您的硬件能够跟上这些事务，以避免超时，即单个查询的时间不能超过5毫秒。

这就意味着你需要一个支持行级锁的存储引擎，比如InnoDB。

另一方面，编写几个简单的脚本来模拟每个存储引擎的负载，然后比较结果应该是相当简单的。

我发现即使Myisam有锁争用，它在大多数情况下仍然比InnoDb快，因为它使用了快速的锁获取方案。我尝试了几次Innodb，总是因为这样或那样的原因回到MyIsam。此外，InnoDB在巨大的写负载下会非常消耗CPU。