Oracle 11 g R2 has more than one table complex query, the query condition is a date, the query is less than 2 seconds in PLSQL can get the result, but will remove the date of the last condition, will be more than the rest of the table made a view associated SQL date conditions to the query of the reoccupy after wait for nearly four minutes , but later found a query view of SQL select after removing the list of fields in the date field, speed back to 2 seconds, the same view in another 11 g R1 database, there is no such a problem, I checked the two involved in the database tables, primary keys, indexes are the same, bosses, please help me to analyse the setting out of the question of where is the database?