Dblink take too long to get data

Question

hi,
i have 9.2.0.7.0 DB on WIN2000
here is the problem:
when i test the DBlinks on this db:
select * from dual@DB_LINK_NAME;
this statement take the whole day !!!!!
i try another DBlink and the same ,
observation:
1-no error on the log file
2-i dont know when this proble happen .(start)
3-the cpu utilization is not 100%
4-no table space is full or more than 80% full
5-sga is:
Total System Global Area 135339876 bytes
Fixed Size 454500 bytes
Variable Size 109051904 bytes
Database Buffers 25165824 bytes
Redo Buffers 667648 bytes
can any one help or any oracle notes may help??

Answer 1

Database links between 9.2 and 8.0.5 are unsupported, and 8.0.5 is unsupported. I would be very concerned about a critical billing application running on an Oracle release that was desupported 8 years ago and isn't even a terminal release that Oracle would have offered extended support on and is 9 major releases behind the current release.
I suppose it's possible that the problem you're seeing is related solely to the fact that you have fundamentally incompatible releases trying to communicate, but normally that sort of thing generates different errors. So I would tend to put my money on Niall's suggestion that there is a firewall between the systems that is interfering with the communication (there are a number of ways this could be happening that would not interfere with a simple ping, so that doesn't tell us much).
If the release compatibility is the problem, is there a third database somewhere running a release that was certified to connect to both 8.0.5 and 9.2 that you could use as a bridge? For example, if you have an 8.1.7 database somewhere, a database link from 9.2 used to be supported and a database link from 8.1.7 to 8.0.5 used to be supported. Of course, then you're making two hops across the network each time, which slows things down, but that would at least eliminate the client/ server incompatibility issues.
Justin