Oracle FAQ Your Portal to the Oracle Knowledge Grid

Home -> Community -> Mailing Lists -> Oracle-L -> Re: Import 8.1.6 to weirdness

Re: Import 8.1.6 to weirdness

From: Govindan K <>
Date: Sat, 17 May 2003 00:46:39 -0800
Message-ID: <>


I have been exporting , importing tables with CLOB (atleast 4-5 CLOB tables per schema) on a regular basis. Not once did i have to shutdown the db. Did you try using the indexfile option of import to pre-create the structure, import and then enable the indexes/constraints? The import to specify grants=n constraints=n indexes=n rows=y ignore=y , after creating the tables.

If you are interested in doing that contact me off the list. I have a unix shell script which will generate 1. Table creation SQL , 2. Index Creation SQL 3. Constraints creation SQL , ALL from the DMP file (In addition you are given the option to change Destination tbs too).
The script creates the indexes using NOLOGGING to make it faster. In addition you can (manully) split into 4 parts and run them in parallel too for still faster results.

Try that and chk the timing. Besides how many rows are there in the CLOB table?. What are the CHUNK size etc. I use buffer=1048576. An improper buffer size too can impact the performance. Having done this much of time, i suggest you do a dummy import on to a different schema in 8.1.6 itself and see the difference in the timing.

Besides, check the following from a different terminal every 30 secs when the import seems to be hanging. SELECT object_type,COUNT(*)
FROM user_objects
GROUP BY object_type

Why i am saying this is because, the options you have used takes INDEXES=Y GRANTS=Y etc (default). May be it is doing that at runtime. You need to check that too.
Besides do a "SELECT COUNT(*) FROM clob_table;" every 15 secs to know the progress.

These two queries + an import in 816 itself will give you an idea of where to look into.

Please post back the results.

HTH GovindanK
OCP 8,8i, Brainbench Certified Master DBA Soon attempting 9i OCP.

|One's lack of planning cannot be someone else's emergency.....|

> Would anyone have any idea what might be going on with the following
> situation?
> I'm importing a 8.1.6 database into a 9.2 database. There are almost 400
> tables and the import seems to chug along fine until I get to a table with
> CLOB column in it. At that point, the import loads in anywhere between a
> few hundred and a few thousand rows of that table and then "hangs". I end
> up having to kill the import session and start over. Actually what has
> mostly happened is that I can't even simply restart but end up having to
> shutdown the database and restart it before I can continue (don't worry
> a new test box so all the ups and downs aren't an issue). Since I'm using
> commit=y and the tables involved all have unique keys, I simply have been
> restarting the import and letting it take off from there.
> Here's my imp command:
> imp id/pswd file=exp816.dmp commit=y ignore=y analyze=n buffer=16384
> fromuser=user1 touser=user2
> I've tried changing the buffer setting from 4K to 64K with no apparent
> effect. I've also tried various other parameter combinations other than
> those listed with no help. The command you see is what seems to work
> The real weird thing is that if I just keep restarting the database and
> restarting the import, the table will eventually load. For one table that
> had 30000 rows, I had to start the import and let it run until it hung,
> shutdown the database and restart the import 10 times to get the full
> to load. Once it loads, the import continues on just fine until it hits
> another table that has a CLOB datatype. Actually it goes one step further
> than just being a table with a CLOB, it's a table with a CLOB that's over
> or so. There are a couple of tables with CLOB columns but the max size of
> the data stored in that column is relatively small. The tables that seem
> have troubles have max size in the CLOB column of over 2K.
> I just need to get this data loaded for test purposes so I can put up with
> the process for the moment, but I can't for the life of me figure out why
> it's acting this way. I've never seen behavior like this.
> Does anybody have any ideas/suggestions or think of anything I may be
> missing somewhere that's causing this problem?
> Many thanks,
> Karen
> ---------------------------
> Karen Morton

Get your free 15 Mb and POP3 email account from
Please see the official ORACLE-L FAQ:
Author: Govindan K

Fat City Network Services    -- 858-538-5051
San Diego, California        -- Mailing list and web hosting services
To REMOVE yourself from this mailing list, send an E-Mail message
to: (note EXACT spelling of 'ListGuru') and in
the message BODY, include a line containing: UNSUB ORACLE-L
(or the name of mailing list you want to be removed from).  You may
also send the HELP command for other information (like subscribing).
Received on Sat May 17 2003 - 03:46:39 CDT

Original text of this message