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From David Van Couvering <da...@vancouvering.com>
Subject Re: Fluctuating disk overhead
Date Mon, 23 Aug 2010 23:33:54 GMT
Yea, that makes sense.  If this were the case, would forcing checkpoints
help the situation?  Can you configure checkpoint frequency, or the maximum
size of the log?

Thanks,

David

On Mon, Aug 23, 2010 at 4:17 PM, Mike Matrigali <mikem_app@sbcglobal.net>wrote:

> 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
>>
>
>


-- 
David W. Van Couvering

http://www.linkedin.com/in/davidvc
http://davidvancouvering.blogspot.com
http://twitter.com/dcouvering

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