Add one more column to a Phoenix Covered Index

[#1]

I have an existing covered index which I created using statement like below.

CREATE INDEX my_index ON my_table (v1,v2) INCLUDE(v3).

Now I want to include one more column v4, like  INCLUDE(v3,v4).  v4 column will not be part of actual index but it will be in covered part.
I am not sure if we have an Alter statement to do this. Request for assistance.

[#2 · Accepted solution]

No, there is no alter for index. The problem is that adding one more column to the index means the same full scan over the table and the operation would be as expensive as the new index creation.

[#3]

I don't want to add one more column to the actual index columns, but in the INCLUDE() section. Will that also have same effect?