… by another factor of ten (it will be 100 disk seeks to answer a random query, assuming you can get each index query down to one disk seek.) I claim that this schema is not properly indexed. Here…
Comment: COUNT(*) for Innodb Tables
March 5, 2012 By 29 Comments
I seek a related clarification: What about the folk developer wisdom that “…
Post: How multiple disks can benefit for single client workload ?
April 26, 2008 By 4 Comments
… too much improvements from optimizing seeks. You can have shorter seeks but as soon as you have any seeks you will be far… to perform the IO operation. When we’re speaking about seeks we imply this rotation as well though people often forget… get 0.2ms track to track seek time (our best case) and 3.5ms average seek time which is significant difference. Now…
Comment: InnoDB Flushing: a lot of memory and slow disk
March 31, 2011 By 57 Comments
… numbers on whether there’s a startup time on disk seeks e.g. what’s the relative cost of moving 1… multiple read heads, the “enveloped assumption” these days is that seek time = 0 on the head e.g. you just assume…/sec) 10k drive -> 3.75 ms seek (267 IOPS/sec) 7.5k drive -> 5 ms seek (200 IOPS/sec) I’m embarassed…
Comment: InnoDB Flushing: a lot of memory and slow disk
March 31, 2011 By 57 Comments
… numbers on whether there’s a startup time on disk seeks e.g. what’s the relative cost of moving 1… multiple read heads, the “enveloped assumption” these days is that seek time = 0 on the head e.g. you just assume…/sec) 10k drive -> 3.75 ms seek (267 IOPS/sec) 7.5k drive -> 5 ms seek (200 IOPS/sec) I’m embarassed…
Comment: InnoDB Flushing: a lot of memory and slow disk
March 31, 2011 By 57 Comments
… “well, I”m already going to have to move the seek head over to location X, so I may as well… to the overall operation isn’t consequential compared to the seek time you already took. I don’t have any brilliant… writes later in another thread that can do some ladder seeking and some some of the write activity.
Comment: InnoDB Flushing: a lot of memory and slow disk
March 31, 2011 By 57 Comments
… “well, I”m already going to have to move the seek head over to location X, so I may as well… to the overall operation isn’t consequential compared to the seek time you already took. I don’t have any brilliant… writes later in another thread that can do some ladder seeking and some some of the write activity.
Comment: InnoDB Flushing: a lot of memory and slow disk
March 31, 2011 By 57 Comments
… one head per platter do not help you with average seek time – there will be only one platter which contains data in specific place, this is where seek will need to happen. In general you’re right SSD…
Comment: InnoDB Flushing: a lot of memory and slow disk
March 31, 2011 By 57 Comments
Peter, Regarding the seek times, yah, I rarely see numbers this good in practice, …’ve seen SANs which do a lot of sophisticated ladder seeking get pretty close, but I don’t think I’ve…
Comment: InnoDB Flushing: a lot of memory and slow disk
March 31, 2011 By 57 Comments
… one head per platter do not help you with average seek time – there will be only one platter which contains data in specific place, this is where seek will need to happen. In general you’re right SSD…
