Oracle - Slow queries without prepending schema name or providing hint

I am logged in as the schema owner in Oracle 11gR2 on Linux. I have 55 million rows in table.

select max(col) from table; - takes 300 seconds (index full scan)

select max(col) from schema.table; - .03 seconds (index full scan min/max)

select /*+ index(tab_col) */ max(col) from table; - .03 seconds (index full scan min/max)

We have similar queries behaving slowly as well until prepending the schema name or using a hint, but this one is the best to demonstrate. This schema was created with impdp remap_schema. The source schema still works well.

What I've tried:

1. Gathered statistics on the schema, then the DB using dbms_stats.


2. We did have a public synonym for table, i removed it and gathered statistics again.


3. expdp/impdp to another server. Queries run fast on the 2nd server. Unable to recreate issue.


4. Dropped Database links then gathered statistics again. No joy.

Any clues? Thank you.