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。

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。

我曾经在一个使用MySQL的大容量系统上工作过，我也尝试过MyISAM和InnoDB。

我发现MyISAM中的表级锁定对我们的工作负载造成了严重的性能问题，这听起来与您的工作负载类似。不幸的是，我还发现在InnoDB下的性能也比我希望的要差。

最后，我通过分割数据解决了争用问题，这样插入就进入了一个“热”表，而选择从不查询热表。

这也允许删除(数据是时间敏感的，我们只保留X天的价值)发生在“陈旧”的表上，这些表同样不会被选择查询触及。InnoDB在批量删除方面的性能似乎很差，所以如果你打算清除数据，你可能想要以这样一种方式来构造它，即旧数据在一个陈旧的表中，可以简单地删除而不是对其进行删除。

当然，我不知道你的应用程序是什么，但希望这能让你对MyISAM和InnoDB的一些问题有一些了解。

对于一个有更多写和读的负载，你将受益于InnoDB。因为InnoDB提供的是行锁而不是表锁，所以你的select可以是并发的，不仅仅是彼此之间的select，还有许多insert。但是，除非你打算使用SQL事务，否则将InnoDB提交刷新设置为2 (innodb_flush_log_at_trx_commit)。这将为您提供大量原始性能，否则将表从MyISAM转移到InnoDB时会损失这些性能。

Also, consider adding replication. This gives you some read scaling and since you stated your reads don't have to be up-to-date, you can let the replication fall behind a little. Just be sure that it can catch up under anything but the heaviest traffic or it will always be behind and will never catch up. If you go this way, however, I strongly recommend you isolate reading from the slaves and replication lag management to your database handler. It is so much simpler if the application code does not know about this.

最后，要注意不同的表负载。您不会在所有表上都有相同的读/写比率。一些接近100%读取的小表可以负担得起MyISAM。同样地，如果你有一些接近100%写的表，你可能会受益于INSERT DELAYED，但这只在MyISAM中支持(对于InnoDB表，DELAYED子句会被忽略)。

但基准是肯定的。

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。