First, thanks for your advice.
> If you want to see whether any of the bugs fixed might be related to
> your error messages, please read the release notes for 8.2.4 to
> 8.2.20 to see which might affect your situation:
> http://www.postgresql.org/docs/8.2/static/release.html
I read all the release notes from 8.2.4 to 8.2.20, but I don't find anything
mentioned/indicated similar to my error message.
> Why in the world would you want to do that? Have you considered
> naming the temporary table differently, like maybe with a _tt suffix
> to denote "temporary table"?
Well, let me explain the long story on why we've named temporary table same
as that of an existing permanent table, in short here. We came to know the
advantage and feature of TEMPORARY tables only at later point of time after
completely developing all PostgreSQL functions (approx. 35 functions) for
running this particular complex report. Also, the existing permanent table
is used for other reports as well in our application, but is not used to the
extent by which this complex report uses. Instead of touching/refactoring
all the 35 functions just to rename the table name, we decided to create the
temporary table name same as that of existing permanent table for running
this complex report alone, so that those tables are automatically dropped at
the end of session and doesn't occupy any disk space also (including its
indexes and toast tables, if any). Hope this makes clear.