Re: DBLINKs in critical production system

  • From: Stephane Faroult <sfaroult@xxxxxxxxxxxx>
  • To: Ajay_Thotangare@xxxxxx
  • Date: Mon, 30 Apr 2007 19:16:26 +0200


Besides security issues (which may not matter too much if your network is secure - I presume, from your address, that it is) and the horror stories about development databases cloned from production (hint: database links had been forgotten in the cloning process), for performance create a sample table (eg create table test_dblink as select * dba_objects where 1=2), then insert into this sample table locally and across the database link under SQL*Plus, with SET TIMING ON. It will tell you if the difference is acceptable to you. From my own experience, database link means performance divided by a factor two (more or less) - and I am talking LAN, not WAN. If once in a while your query takes 0.8 seconds instead of 0.4, nobody will care. If you have a batch that repeats the query 2 million times, it will run 0.4 * 2,000,000 seconds slower, and you may have some grumpy individual objecting to the batch taking one day longer than usual. As usual, it depends.


Stéphane Faroult

Thotangare, Ajay (GTI) wrote:

Yes I agree with your explanation. How different it is accessing data from db link and direct connection without dblink considering I have a very good separate IP/card for dblink




*From:* Mitchell, Travis [mailto:Travis.Mitchell@xxxxxxxxxxxxxxxx]
*Sent:* Monday, April 30, 2007 11:03 AM
*To:* Thotangare, Ajay (GTI); oracle-l@xxxxxxxxxxxxx
*Subject:* RE: DBLINKs in critical production system

Imagine sticking a post-it with username/password information on your monitor… db_links are just about the same, especially pre-10g because the passwords are not encrypted.

I’ve walked in and found that my database is hung because I did a developer a favor so they could quickly pull some data from a production system. Their sql took forever, backup software tried to shutdown the development database but couldn’t because of said sql, ORA-600s and some relationship building with Oracle support ensued. This was pre audit everything requirements, so I would recommend that if you have to use them, make sure your security team and the business has it approved in writing. Technically they can cause problems but from a security standpoint you can be heavily exposed.

-----Original Message-----
*From:* oracle-l-bounce@xxxxxxxxxxxxx [mailto:oracle-l-bounce@xxxxxxxxxxxxx] *On Behalf Of *Thotangare, Ajay (GTI)
*Sent:* Monday, April 30, 2007 10:43 AM
*To:* oracle-l@xxxxxxxxxxxxx
*Subject:* DBLINKs in critical production system

Hi Group,

I have a question about dblink. I always hear that

- dblinks are not good in production system.

- dblink , ohh!! not in critical production system

- dblink are not safe

Can anybody please let me know the reason for such comments on dblinks.




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