Re: Using SQL*Net from V6 to V7 databases

John Blackburn (jb2_at_qdot.qld.gov.au) wrote:

> At our site, we have a number of SUN Sparc 10's all on SunOS 4.1.3
> running various Oracle databases.
 

> One of these machines is running Oracle 7.1.3
> and SQL*net version 1.2.7.7.1
 

> There is no problem accessing other remote databases on our site from this
> machine.
 

> The rest of our machines are running Oracle 6.0.36.7.1
> and SQL*Net 1.2.7.6.1 or 1.2.7.3.1
 

> There is no problem using database links between any of the Version 6
> databases
 

> However, if I do
> SELECT * FROM DUAL_at_DBLINK;
> when DBLINK is a link to the version 7 database from a version 6 database
> I get differing error messages depending on the version of SQL*Net.
 

> when SQL*net is version 1.2.7.3.1 the error messages are
 

> ORA-02068 following severe error from [v7 database hostname]
> ORA-03113 end-of-file on communication channel

> when SQL*net is version 1.2.7.6.1 the error message is
 

> ORA-03106 fatal two-task communication protocol error

> What is the cause of these error messages
> and how do I get them to go away?
 

> Is there some incompatability between V6 and V7 that does not allow
> a V6 database link to a V7 database?
> Or is there an incompatibility problem between SQL*Net 1.2.7.3.1/1.2.7.6.1
> and SQL*Net 1.2.7.7.1?

> (When we have the available resources, we will be upgrading all our databases
> to V7.)

This is unusual, I got a response from Oracle faster than I got one from this news group.

According to Oracle, there is a bug in Version 6 which caused the problems connecting to a 7.1 database. (The problem doesn't happen connecting to a version 7.0 database.)

Oracle have a patch for 7.1.3 which allows the version 6 database to talk to the version 7.1 database. (curious the way they patch the version 7 database to get around a version 6 problem.)

The only catch with the patch is that you require 6.0.37 for the patch to work (If we had the time and resourses to upgrade all our 6.0.36 machines to 6.0.37 then we'd be going straight to 7.1.3 (or possibly 7.1.4))

Another way around the problem is to have a 7.0 database that has a link to the 7.1 database, and set up synonyms for all the 7.1 tables in the 7.0 database, and creating a database link from 6 to the 7.0 database. And there is no need for a patch using this method. (this sounds very roundabout, but it works.)

With our current setup and resourcing, the second method has been the most cost effective solution

John.

--
 
John Blackburn                                          Phone: +61 7 2534634
jb2_at_qdot.qld.gov.au                                     Fax:   +61 7 8541194