Indexing effect on performance while insert , update in oracle database?

Question

I have indexing on columnA , columnB and ColumnC. I have an update query running which is updating columnB and there is another query which is updating columnC initially columnB and columnC will be null.

I have find query which has where clause

Select * from Tablename where columnA="xyz" or columnB="xyz" or columnC="xyz" ;

I am looking to add composite index on these columns. I want to know what will happen if we run update query does index rebuild every time on all three columns ?

Answer 1

if we run update query does index rebuild every time on all three columns?

When the data in the table changes, the system will perform the required updates on the table's indexes. This will not be a complete rebuild.