Question : SELECT statement never completes over db_link

Here's the setup.

I have a a timekeeping application written in Forms 4.5 running on Oracle 8.1.7.4 on HP-UX 11.00 (yes, it's very old).

This application validates work orders (among other things) against a work management system - two different installations of the work management systems in fact.

One site validates to an Oracle database (9.2.0.7 on HP-UX 11i v1) via a DB Link.
The other site validates to a SQL Server 2005 database via a DB Link using Oracle Heterogeneous Services as the transport.

It's been working fine for 6 months.  Today, things went a little haywire.

Queries validating against tables other than the work order table work fine.  As soon as we hit the work order table, it times out and stops responding - when querying against either work management system.

The common denominator is the timekeeping database so we bounced it. No change.

To throw another monkey into the works we have a clone of the timekeeper server (same configuration) that we've been using to test some other stuff.   It only has a link to the SQL Server database.   I can query the work order table on the SQL Server database from the clone just fine.

Even a simple SELECT COUNT(*) sits and spins forever and never returns.

Looking for any assistance or ideas as to what might be going on here.   Since the clone server works, I'm thinking that there's something on the original server that's not quite right.   I may even try rebooting it tomorrow.   (It did do an automated reboot on Saturday night and even though the system log and the oracle alert log all show no abnormalities, I wonder if something screwed up in there somewhere...)

Answer : SELECT statement never completes over db_link

this result you get when session is hung??

if so your way seems to be the one from Finding Blockers section of Note 34579.1