Hi Monty,
On May 5, 2010, at 7:02 PM, Michael Widenius wrote:
"Paul" == Paul McCullagh <paul.mccullagh@xxxxxxxxxxxxx> writes:
<cut>
Paul> PBXT can help you out with this. Do the following:
Paul> (1) Load the telpbxt table with a few 1000 rows (or use
telpbxt2,
Paul> since telpbxt already has too many rows in it).
Paul> (2) In mysql client enter: CHECK TABLE telpbxt2; (note: do
not do this
Paul> on a table with millions of rows. It will take very long to
complete).
Paul> (3) Check the MySQL error log, you should see something like
the
Paul> output below.
Paul> CHECK TABLE: ./test/telpbxt
Paul> Record buffer size = 1024
Paul> Fixed length rec. len. = 1020
Paul> Handle data record size = 638
Paul> Min/max header size = 14/26
Paul> Min/avg/max record size = 19/624/1019
Paul> Avg row len set for tab = not specified
Paul> Rows fixed length = NO
Paul> Maximum fixed size = 16384
Paul> ...
Paul> Paste the output in an e-mail, and I will show you what to
use for the
Paul> AVG_ROW_LENGTH.
Would it be hard for PBXT to as part of the CHECK TABLE add:
Optimial create AVG_ROW_LENGTH: ?
Currently CHECK TABLE prints:
Average comp. rec. len. = 200
This is the closest to your suggestion of an "Optimal create
AVG_ROW_LENGTH", there is at the moment.
But, this value is not necessarily optimal.
Exactly what is optimal depends on a few additional factors, like
whether you want to optimize for size or caching behavior.
What I can do is add more information to help in this decision
making process, and output a "Recommended AVG_ROW_LENGTH".
Then I can change OPTIMIZE TABLE to automatically set this value,
if no explicit AVG_ROW_LENGTH has been set yet.
Best regards,
Paul
--
Paul McCullagh
PrimeBase Technologies
www.primebase.org
www.blobstreaming.org
pbxt.blogspot.com
