When running a "Select * from table_name" or just going to the data tab in the Object Explorer, the default for Toad is to initially fetch 1000 rows. Then when you scroll to the bottom of the list, Toad asks if you want to fetch ALL data. If the table is large, this action would take a long time to return all the rows.
You can filter the amount of data by using “fetch first xx rows only” for instance. When you click the icon below, you can enter “fetch first xx rows only” in the where clause. In this way, the number of records to display will be limited to your liking. You can also use different filters aside from adding a where clause like the above.
If the table is too large, e.g. 1 Million records, it’s a very inefficient way to access the database with millions of records with “select *” command as this will really fetch all records in the table. You would need to tune the query or be exact, by adding the where clause rather using “select *” command.
