MySQL 的 read_buffer_size 参数是如何影响写缓冲和写性能的？

来自国外博客的一篇文章介绍了MySQL 的 read_buffer_size 参数是如何影响写缓冲和写性能。

据说 read_buffer_size 参数只影响以下两种情况的写数据的性能：

SELECT INTO … OUTFILE ‘fileName‘

When writing to the OUTFILE, the writes are buffered before writing to OUTFILE

When filesort is used, during merge buffers and when merged results are written to a temporary file, then writes are buffered

下表是该文章测试的一些数据：

read_buffer_size	physical writes	exe time in secs
=0 (defaults to 8200)	23495	28.39
=131072 (default)	2937	27.44
=16777216	23	26.71
=33554432	12	26.00
=536870912	1	26.72

详细内容请看原文：

http://venublog.com/2010/06/23/how-read_buffer_size-impacts-write-buffering-and-write-performance/