Submitted by: K. A. (parshua)

We use EXTERNAL TABLES like external databases, meaning we use them when we have some data that we do not want to go into the database (due to many reasons), but we still want to be able to select and join from that table. In many cases, the EXTERNAL TABLE itself is much bigger than the whole database, and is read-only, and is rarely replaced by another updated file.

To let you have an idea of the scheme, let us assume that we have a database that records some transactions about some customers, but the Customer table is populated elsewhere. The Customer data is huge, but rarely updated, and the database itself is smaller, but regularly needs to be sent to many sub departments. this was not an actual case, but I hope it gives you the idea. Due to security/infrastructural reasons, online or live replication is not possible, so the database have to be ported by physical storage medium (CD/DVD)

The only thing that makes this difficult is that when the data in EXTERNAL TABLE grows and the record count passes some few tens of million records, statements that query the ET become very very slow, particularly on left joins.

Being able to index ETs would help us overcome this problem, and it will make ETs work like full fledged database tables.
If the index file could be kept beside the external file would be great, as it can be ported with the ET file and does not need to be indexed again in the destination.