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From Mike Matrigali <mikem_...@sbcglobal.net>
Subject Re: Fluctuating disk overhead
Date Mon, 23 Aug 2010 23:17:26 GMT
David Van Couvering wrote:

It will probably be a lot easier to explain if you du
the "log" directory and the "seg0" directory separately
each time.  And for more detail do a ls -l of the "log"
directory.  My guess is that it is due to logging, and
incremental log file cleanup, but would need more data
to confirm.

> Sorry, about that, new mouse and I did a premature send...
> 
> As I was saying...
> 
> Here is the table definition:
> 
> CREATE TABLE BLOBTEST(ID INTEGER PRIMARY KEY, BLOBCOL BLOB)
> 
> I insert 100 rows, and then do a loop updating the 100 rows over and 
> over again.
> 
> When I watch the disk usage of the database directory, I see this 
> pattern repeated over and over again.
> 
> I tried adding a call to compress the table after every 100 updates, but 
> this had no impact.
> 
> Can you explain what is going on and what, if anything, I can do to keep 
> the size small?
> 
> Thanks,
> 
> David
> 
> $ du -s -h BLOBTEST
> 3.3M    BLOBTEST
> 
> $ du -s -h BLOBTEST
> 3.4M    BLOBTEST
> 
> $ du -s -h BLOBTEST
> 4.9M    BLOBTEST
> 
> $ du -s -h BLOBTEST
> 5.9M    BLOBTEST
> 
> $ du -s -h BLOBTEST
> 6.5M    BLOBTEST
> 
> $ du -s -h BLOBTEST
> 7.0M    BLOBTEST
> 
> $ du -s -h BLOBTEST
> 8.6M    BLOBTEST
> 
> $ du -s -h BLOBTEST
> 8.7M    BLOBTEST
> 
> $ du -s -h BLOBTEST
> 8.7M    BLOBTEST
> 
> $ du -s -h BLOBTEST
> 9.7M    BLOBTEST
> 
> $ du -s -h BLOBTEST
> 11M     BLOBTEST
> 
> $ du -s -h BLOBTEST
> 12M     BLOBTEST
> 
> $ du -s -h BLOBTEST
> 11M     BLOBTEST
> 
> $ du -s -h BLOBTEST
> 13M     BLOBTEST
> 
> $ du -s -h BLOBTEST
> 14M     BLOBTEST
> 
> $ du -s -h BLOBTEST
> 4.3M    BLOBTEST
> 
> On Mon, Aug 23, 2010 at 10:49 AM, David Van Couvering 
> <david@vancouvering.com <mailto:david@vancouvering.com>> wrote:
> 
>     Hi, all.  I have a test that updates 100 rows, each of which
>     contains an int primary key and a 300-byte BLOB:
> 
>      
> 
>     -- 
>     David W. Van Couvering
> 
>     http://www.linkedin.com/in/davidvc
>     http://davidvancouvering.blogspot.com
>     http://twitter.com/dcouvering
> 
> 
> 
> 
> -- 
> David W. Van Couvering
> 
> http://www.linkedin.com/in/davidvc
> http://davidvancouvering.blogspot.com
> http://twitter.com/dcouvering


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