> now, if you are inside a read only transaction, you can't insert data into a GTT
> but GTT are useful to some long running select queries or even to make a set of successive
> select queries
> since GTT have a flag and that data are outside the db file, wouldn't be possible to allow
> insert even on read only transaction ?

What is the use case for such requirement?

Some time ago we had requirement, where people asked to allow CRUD
operations in the databases on read-only media (e.g. CDROM), where the
additional file would have been located, for example, in %TEMP%
directory. The use case for such requirement was to allow modification
of user-specific data for a "dictionary" databases distributed on CDROMs
and DVDs.

And, if I understand correctly, the "main" technical issue is that main
database file must be updated in the system tables area (OAT, OIT,
allocate pages, etc).

Roman