On Mon, Nov 05, 2001 at 07:15:31PM -0700, Michael Griffith wrote:
>
> Either the key cache is inefficient or I misunderstand it. Can
> anyone explain this?
>
> Before query:
>
> | Key_blocks_used | 530300 |
> | Key_read_requests | 56072940 |
> | Key_reads | 527026 |
>
> Query executed, takes 30+ seconds
>
> After Query
>
> | Key_blocks_used | 530300 |
> | Key_read_requests | 56092143 |
> | Key_reads | 527026 |
>
> No increase in key_reads, so lookup came from cache
>
> Same Query run again takes 0.11 seconds (272 times faster)
Interesting.
Even if all the key blocks where in memory (and not swapped
out--you're not using Linux 2.4.x, are you?), there's the data itself.
The rows may not have been cached the first time, but the second time
they probably were.
Jeremy
--
Jeremy D. Zawodny, <jzawodn@stripped>
Technical Yahoo - Yahoo Finance
Desk: (408) 349-7878 Fax: (408) 349-5454 Cell: (408) 685-5936
MySQL 3.23.41-max: up 61 days, processed 1,335,559,153 queries (253/sec. avg)
