Hi,
According to the manual - 
http://dev.mysql.com/doc/mysql/en/OPTIMIZE_TABLE.html
http://dev.mysql.com/doc/mysql/en/InnoDB_File_Defragmenting.html

running a null ALTER statement - ALTER TABLE tbl-name type=INNODB; will 
rebuild the table thus optimizing the way the table is written to the disk. 
It will fix the physical ordering of the index pages on the disk thus 
improving the time MySQL needs to perform an index seek. It will not decrease 
the space used by the INNODB file but it could speed things up. If you want 
to regain some of the space used by the INNODB file you will have to convert 
all INNODB tables to MYISAM (or dump them to a SQL file), recreate the INNODB 
file (s) and then recreate the original INNODB tables. This process could 
take a  lot of time depending on the size of your tables so you should 
proceed with care.


HTH

-- 
Dobromir Velev
[EMAIL PROTECTED]
http://www.websitepulse.com/

On Thursday 07 October 2004 22:07, Boyd E. Hemphill wrote:
> The documentation is not clear on this point.  Here is a quote:
>
> 'For BDB tables, OPTIMIZE TABLE is currently mapped to ANALYZE TABLE. It
> was also the case for InnoDB tables before MySQL 4.1.3; starting from this
> version it is mapped to ALTER TABLE.'
>
> What is meant by its being mapped to ALTER TABLE?  Too, what exactly
> happens after 4.1.3?  Is space, in fact, recovered and defragged?
>
> Thanks for your time!
>
> Best Regards,
> Boyd E. Hemphill
> MySQL Certified Professional
> [EMAIL PROTECTED]
> Triand, Inc.
> www.triand.com
> O:  (512) 248-2278
> M:  (713) 252-4688
>
> -----Original Message-----
> From: Christopher L. Everett [mailto:[EMAIL PROTECTED]
> Sent: Wednesday, October 06, 2004 6:23 PM
> To: 'Mysql List'
> Subject: Re: Repeated corruption with MySQL 4.1.x using FULLTEXT indexes
>
> Ed Lazor wrote:
> >>-----Original Message-----
> >>From: Christopher L. Everett [mailto:[EMAIL PROTECTED]
> >>Sent: Wednesday, October 06, 2004 1:47 AM
> >>To: Mysql List
> >>Subject: Repeated corruption with MySQL 4.1.x using FULLTEXT indexes
> >>
> >>I have an application where I create a faily large table (835MB) with a
> >>fulltext index.  One of our development workstations and our production
> >>server will run the script to load the table, but afterwards we have a
> >>pervasive corruption, with out of range index index pointer errors.
> >>Oddly, my development workstation doesn't have those problems.
> >>
> >>My box and the ones having the problems have the following differences:
> >>
> >>  - my box runs ReiserFS, the problem boxes run XFS
> >>  - my box has a nice SCSI HD subsystem, the problem boxes do IDE.
> >>
> >>All three boxes run Linux 2.6.x kernels, and my workstation and
> >> production server share the same mobo.  Come to think of it, I saw
> >> similar corruption issues under 2.4.x series kernels and MySQL v4.0.x,
> >> it just wasn't the show stopper it is now.
> >>
> >>Also, on all three boxes, altering the table to drop an index and create
> >>a new one requires a "myisamchk -rq" run afterwards when a fulltext index
> >>either exists or gets added or dropped, which I'd also call a bug.
> >
> >The problems you're describing are similar to what I've run into when
> > there have been hardware related problems.
> >
> >One system had a problem with ram.  Memory tests would test and report ram
> >as ok, but everything started working when I replaced the ram.  I think it
> >was just brand incompatibility or something odd, because the ram never
> > gave any problems in another system.
>
> I can generate the problem on much smaller data sets, in the mid tens of
> thousands of records rather than the millions of records.
>
> I'll do a memtest86 run on the development boxes overnight, but as I did
> that
> just after I installed linux on them and used the linux badram patch to
> exclude
> iffy sections of RAM, I don't think thats a problem.
>
> >One system had hard drive media slowly failing and this wasn't obvious
>
> until
>
> >we ran several full scan chkdsks.
>
> 3 hard drives all of different brand, model & size, and the problem
> happening
> in the same place on both?  Not likely.
>
> >The funniest situation was where enough dust had collected in the CPU fan
>
> to
>
> >cause slight over heating, which resulted in oddball errors.
>
> This isn't a problem on my box.  I have a 1.5 pound copper heatsink with a
> 90mm heat sensitive fan and a fan+heatsink for the hard drive, and I saw
> myisamchk consistently generate the same error in the same place over and
> over.  The sensors report my CPU running in the 45 degree centigrade range
> on my box pretty consistently.
>
> >In each of these cases, everything would work fine until the system would
> >start processing larger amounts of data.  Small amounts of corruption
> > began to show up that seemed to build on itself.
> >
> >This may or may not relate to what you're dealing with, but maybe it will
> >help =)
>
> I'll look, but I don't think that's the problem.   I'm going to see how
> small
> of a data set will cause this problem and file a bug report.
>
> --
> Christopher L. Everett
>
> Chief Technology Officer                               www.medbanner.com
> MedBanner, Inc.                                          www.physemp.com
>
>
> --
> MySQL General Mailing List
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