mysql Out of memory (Needed 16777224 bytes)的错误解决

这几天碰到这个错误。 
至于我改的这几个值是不是正确的解决方法，目前还不知道。先贴出来。 
如果过一段时间我还是没有更新，那以后同志们都参考吧 。 
Out of memory (Needed 16777224 bytes)的错误解决 
看看手册： 
[url]http://dev.mysql.com/doc/refman/5.1/en/memory-storage-engine.html[/url] 
开始我更改了query_cache_size的值。 
好像也不行。 
之后 
增大query_cache_limit 的值。 
还有max_heap_table_size 
和tmp_table_size的值。 
因为我们的存储过程中用了好多的预处理语句。而且语句的结果都是非常大的。 
起初我的结果： 
mysql> show variables like 'max_heap_table_size'; 
+---------------------------------+----------------------+ 
| Variable_name | Value | 
+---------------------------------+----------------------+ 
| max_heap_table_size | 16777216 | 
+---------------------------------+----------------------+ 

mysql> show variables like 'tmp_table_size'; 
+---------------------------------+----------------------+ 
| Variable_name | Value | 
+---------------------------------+----------------------+ 
| tmp_table_size | 16777216 | 
+---------------------------------+----------------------+ 

我改了my.cnf文件 

mysql> show variables like 'max_heap_table_size'; 
+---------------------------------+----------------------+ 
| Variable_name | Value | 
+---------------------------------+----------------------+ 
| max_heap_table_size | 67108864 | 
+---------------------------------+----------------------+ 

mysql> show variables like 'tmp_table_size'; 
+---------------------------------+----------------------+ 
| Variable_name | Value | 
+---------------------------------+----------------------+ 
| tmp_table_size | 67108864 | 
+---------------------------------+----------------------+ 

顺便看一下这篇文章中的一段话： 
http://dev.mysql.com/tech-resources/articles/mysql-query-cache.html 

Qcache_hits and Qcache_inserts shows the number of times a query was serviced from the cache and how many queries have been inserted into the cache. Low ratios of hits to inserts indicate little query reuse or a too-low setting of the query_cache_limit, which serves to govern the RAM devoted to each individual query cache entry. Large query result sets will require larger settings of this variable. 

补充： 
今天在手册上看到这段话 

http://dev.mysql.com/doc/refman/5.1/en/out-of-memory.html 
If you issue a query using the mysql client program and receive an error like the following one, it means that mysql does not have enough memory to store the entire query result: 

所以我把我的所有存储过程都修改了。 
因为里面的预处理语句没有清零。 
经过测试。 
比如： 
里面用到 
PREPARE S1 FROM @STMT; 
... 
一定要 
SET @STMT = ''; 
不知道这个是不是根本原因。我会再次更新的。 
再次证明这样做会减少这种情况。不过下午把所有存储过程修改了。 
凡是普通连接的都改为LEFT JOIN 了。通过EXPLAIN建立了相关索引。 
而且把版本换成了5.0.45。至于是否还是出现错误。还在继续关注中。。。目前没有任何错误。 

这个问题貌似MYSQL官方解决了。 
http://bugs.mysql.com/bug.php?id=31898