Does innodb_flush_method affects read operation?

If I set innodb_flush_method=O_DIRECT, will the read operation of innodb bypass the syste开发者_如何学Pythonm cache? Thanks!

innodb_flush_method have nothing to do with reading, it's about the write cache.

InnoDB actually reads from the buffer pool, which is loaded in RAM. If the data is not available in the buffer pool, it fetches a page, containing the requested data and load it in the buffer pool. I'm not sure for which cache you are asking for, and can't tell for sure if it will hit system cache, but the chance the data to be presented in the system cache, and not in the buffer pool, IMO is zero.