Re: Improving N-Distinct estimation by ANALYZE

On Mon, 2006-01-09 at 22:08 -0500, Greg Stark wrote:

> So it's not the 8k block reading that's fooling Linux into reading ahead 32k.
> It seems 32k readahead is the default for Linux, or perhaps it's the
> sequential access pattern that's triggering it.

Nah, Linux 2.6 uses flexible readahead logic. It increases slowly when
you read sequentially, but halves the readahead if you do another access
type. Can't see that would give an average readahead size of 32k.

Anyway.... this is one just reason for change...

Best Regards, Simon Riggs