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No conference for me, *sniff*

*Sigh*, well I won't be making it out to the conference this year:  My wife is due any day now with our third child.  Scheduling to fly to California next week just doesn't seem like it falls under the category of "supporting my wife."  


Top ten things I'll miss about the mysql conference 2008:
  1. How replication is dead
  2. Why 5.1 isn't stable yet
  3. How wonderful Sun/Maria/Falcon/Cluster/6.x/Proxy is
  4. Grilling Heikki about Innodb internals and bottlenecks
  5. Wringing more information about high performance MySQL from Paul Tuckfield
  6. The food!
  7. Vendor / O'Reilly Swag
  8. How great MySQL will run on Sun hardware
  9. Conference Day 3 daze -- that part of the conference where your eyes start to glaze over. 
  10. Getting really, really sick of talking about MySQL
Have fun everyone, see you next year!

Letters to the Editor (1)

I recently got this email from a reader on my site and since I haven't posted for a while, I thought it might be a good discussion:


Jay,

I've been reading your site and had a question that you might have good insight for.  

I'm working on a high-traffic website that includes forums.  All the code is custom PHP, including the forums, simply because the PHP BB software out there doesn't scale as large and as well as I wanted.  I've implemented heavy memcached usage, distributed databases, etc. to handle any level of growth we may hit.

The scoop on Innodb reads

I spent some time going through the source the other day in order to try to understand the difference between these SHOW STATUS variables in 5.x:


Innodb_buffer_pool_read_requests
Innodb_buffer_pool_reads
Innodb_pages_read

Here's what I discovered that I'm not sure is 100% right, but I suspect is at least on the right track:

Innodb_buffer_pool_read_requests:  requests to get something from the buffer pool.  This isn't really that great of a mystery.  I suspect these are 'direct' read requests, meaning those caused directly from a query of some kind.  

MyQ Gadgets 0.0.9 released

A new version of myq_gadgets has been released and you can download it here.


Changelog since the last released version here:
Version 0.0.9 -
    - Documented new reports in README
    - Updated 'thds' column in the 'cttf' report to read 'crtd' instead.
Version 0.0.8 -
    - Added a bunch more innodb reports, looking for the good stuff.
Version 0.0.7 -
    - Added an 'innodb' mode to myq_status to support 5.0+ STATUS variables.
      'myq_innodb_status' continues to handle SHOW INNODB STATUS output,
      mostly for 4.1 and earlier.
    - Beefed up the format_memory function to use recursion to determine the
      appropriate output multiplier (tera, giga, mega, kilo, etc.)


STATUS variables: the difference between innodb_pages_read and innodb_buffer_pool_reads

I haven't gotten any responses to my question from Friday, so I figured I'd post a more direct question:


The two variables 'innodb_pages_read' and 'innodb_buffer_pool_reads' are different.  'Innodb_pages_read' seems consistently higher than the buffer_pool_reads.  Certainly the buffer pool reads 'pages', but what else would be counted as a page read?


On the flip side, 'innodb_pages_written' and 'innodb_buffer_pool_pages_flushed' seem consistent.  

Anyone have any clues?

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Jay Janssen
Yahoo!, Inc.
jayj at yahoo dash inc dot com

MySQL
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