Hi, fellows

I have Informix 7.30.UC10, running on HP Unix. When I put data, larger
than 1MB into BYTE column using JDBC driver version 2.21.JC3 (JDK
1.4.2), it takes very long time to finish the operation. For example,
if the data is 1MB it takes 23 secs. When I try to put 18MB, the
duration of that operation is 440 secs and checkpoint duration in the
online.log is 10 secs - is it too long?

Did someone face this problem?
Any solutions?

Thank you for your help.

Georgi Cholakov
ISY Intellect
g.cholakov (AT) isy-dc (DOT) com

On 8 Oct 2004 00:20:55 -0700, g.cholakov (AT) isy-dc (DOT) com (Georgi Cholakov)
wrote:

Is the BLOB column stored in a regular dbspace or in a blobspace? Any
BLOB data stored in a regular dbspace will go through the buffers . .
..
JWC

The BLOB is in dbspace. I will create a blobspace and make a test again.

Thank you for your help.

Georgi Cholakov

I created a blobspace and then created the table again, using the
following command:

CREATE TABLE BLOBTEST
(
ID INTEGER PRIMARY KEY,
BLOBCOL BYTE IN BLOBSPACE1
)

But the time needed to write data in this column (blobcol) is the same
as previous, when the blobcol was IN TABLE, not in BLOBSPACE1.

Am I missing something?

Thank you for your time.
Georgi Cholakov

Hi !

The tests that I have done show the same result as you get. I thought
it was a problem using JDBC so I did the same thing with a 4GL program
and got the same result. It seems that storing large blobs takes a
long time. I also looked at other databases and found similar problems
noted for them.

If you use a smart blob space (version 9.X) and turn off the logging
it will be a lot faster, but you will sacrifice the benefits that
logging will give. The solution that we are using now is to store the
data in a file in the filesystem and then pick it up using a servlet
that then stores the file in a blobcolumn in the database. From the
user perspective it is very fast to store large objects, and it is
then stored in the database a few seconds later, transaction logging
is used in this case. Of course this method is not a 100 % safe, but
close enough for our purposes.


Regards


Ulf



g.cholakov (AT) isy-dc (DOT) com (Georgi Cholakov) wrote in message news:<be9f1956.0410112156.348fcecc (AT) posting (DOT) google.com>...

It would be interesting to know your blobpage size when using a blobspace ...

onstat -d for the blobspace should show it.

Problem with blobspaces is they are really optimized for "blobs of a similar size", so they are not really effective if you have a wide range of blobsizes (e.g. 50% are 2k in size and then 50% are 2 Mb in size).

If you have a requirement for "large blobs" which are all generally around 2 Mb then you could consider creating a blobspace with a 2 Mb blobpage size using "-g pagesize" argument to onspaces.