[Solved] oracle 11g execution plan behaviour

How to optimize this SQL query?

In case you have your own slow SQL query, you can optimize it automatically here.

For the query above, the following recommendations will be helpful as part of the SQL tuning process.
You'll find 3 sections below:

  1. Description of the steps you can take to speed up the query.
  2. The optimal indexes for this query, which you can copy and create in your database.
  3. An automatically re-written query you can copy and execute in your database.
The optimization process and recommendations:
  1. Avoid Selecting Unnecessary Columns (query line: 2): Avoid selecting all columns with the '*' wildcard, unless you intend to use them all. Selecting redundant columns may result in unnecessary performance degradation.
  2. Create Optimal Indexes (modified query below): The recommended indexes are an integral part of this optimization effort and should be created before testing the execution duration of the optimized query.
Optimal indexes for this query:
CREATE INDEX booking_grid_idx_hotel_bookingstate ON BOOKING_GRID (hotel,BOOKINGSTATE);
CREATE INDEX booking_states_idx_rowid ON BOOKING_STATES (ROWID);
The optimized query:
SELECT
        * 
    FROM
        BOOKING.BOOKING_GRID BG,
        BOOKING.BOOKING_STATES BS 
    WHERE
        BG.hotel = 128 
        AND BS.ROWID = BG.BOOKINGSTATE

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* original question posted on StackOverflow here.