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