>-----Original Message-----
>From: Ann W. Harrison [mailto:ann@stripped]
>Sent: Monday, February 15, 2010 12:12 PM
>To: Martijn Tonies
>Cc: mysql@stripped
>Subject: Re: how things get messed up
>
>There are lots of ways to screw up storage.
>
[JS] As the one who started this topic, I can't agree more. I was away for
several days, but I must insert that I'm not a novice (although I haven't
looked at the internals of a database for several years). Some of the things
that can affect data transfer between the client and the physical storage are:
- Seek time of the mechanics
- Internal buffering in the physical drives
- Delayed writing at the device level
- Ability, or lack thereof, of the drives and/or controllers to chain commands
- Ability, or lack thereof, of the drives and/or controllers to reorder
chained commands
- Raid level
- Buss speed
- Raw vs. file system storage
- Fragmentation of the file allocation on the disks
- Ability of the file system to do anticipatory reads
- File system buffer strategies
- File system buffer size/number
- Database engine buffer strategies
- Database engine buffer size/number
- Fragmentation of the tables within the data file (if applicable)
- Fragmentation of the data within the tables
- Design of the database/tables
- Ability of the engine to optimize queries
- Ability of the programmer to write sane queries
- Use, design, and optimization of stored procedures
- Speed of the pipe between the client and the database host
- Efficiency of the database access library
- Language in which the client application is written (compiled vs.
interpreted being the big differentiator)
- Efficiency of the client's handling of the retrieved data
- Efficiency of the presentation layer
- Speed of the pipe between the client and the user
- ROI on optimizing any or all of the above
- Management meddling
A profiler that could integrate all of the above would be a nifty tool,
wouldn't it?
Regards,
Jerry Schwartz
The Infoshop by Global Information Incorporated
195 Farmington Ave.
Farmington, CT 06032
860.674.8796 / FAX: 860.674.8341
www.the-infoshop.com
>Cheers,
>
>Ann
>
>
>
>
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