Question about table scan

[mahajanakhil198]

See the following query:

select a from test where c=10;

Suppose we have a composite index on columns(c,a). Will all the data in this case be retrieved using index without actually referring the base table?

[davey23uk]

have you tested it - to try and learn?

[mahajanakhil198]

As simple 'yes' wouldn't have killed you. I asked it because I was home and it was teasing my mind and I didn't have access to some Oracle Installation. I just tested it. It is Index Fast Full Scan feature.

[PAVB]

it actually depends on cardinality ... optimizer may decide or not to rely on index depending on percentaje of rows expected to be retrieved.

[stecal]

As simple 'yes' wouldn't have killed you. I asked it because I was home and it was teasing my mind and I didn't have access to some Oracle Installation. I just tested it. It is Index Fast Full Scan feature.

Installing Oracle on a home PC won't kill you either.

[mahajanakhil198]

Installing Oracle on a home PC won't kill you either.

haha. This is being blown out of proportion. That requires copying a dump from office system and that's a kind of breach.