An article from a foreign blog describes how MySQL's read_buffer_size parameters affect write buffering and write performance.
It is said that the Read_buffer_size parameter only affects the performance of write data in the following two scenarios:
- SELECT into ... OUTFILE 'fileName'
- When writing to the OUTFILE, the writes is buffered before writing to OUTFILE
- When Filesort was used, during merge buffers and when merged results was written to a temporary file, then writes was Buffe Red
The following table is some of the data that this article tests:
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 |
For details, please read the original text:
http://venublog.com/2010/06/23/how-read_buffer_size-impacts-write-buffering-and-write-performance/
How does MySQL's read_buffer_size parameter affect write buffering and write performance?