Indexing column for full text search

Question

I have column col with data type CHARACTER VARYING

I need that index this column as gin index. If trying directly set gin index to column, returned error:

data type character varying has no default operator class for access method "gin" HINT: You must specify an operator class for the index or define a default operator class for the data type

If trying:

 create index col_vector 
 on mytable 
 using gin (to_tsvector(col))

I got error: functions in index expression must be marked IMMUTABLE

How to create gin index for CHARACTER VARYING column ?

p.s. I need this for full text search

Answer 1

Try This Code:

CREATE INDEX "name " ON "tablename" USING gin(to_tsvector('english', "columnname"));